It's difficult to play with Fomantic's ".link" selector&styles, and it
doesn't bring any real benefit.

Instead, it sometimes introduces regressions (because of the `:not`
selector, really difficult to fine-tune).

Regression:

<details>


![image](https://user-images.githubusercontent.com/2114189/229421849-b48fbcf6-2ae2-4264-b06b-2a06c12e1a4b.png)

</details>

After this PR, there is no ".link" in code anymore. We do not need to
play the overwriting and `:not()` game anymore.


![image](https://user-images.githubusercontent.com/2114189/229422058-476aa5e2-53db-402d-b507-a6063824f835.png)


![image](https://user-images.githubusercontent.com/2114189/229422435-34fde1bc-b2ec-48ec-8c4a-6d8c2610b249.png)


![image](https://user-images.githubusercontent.com/2114189/229422014-cb38c8c7-828f-4a49-a761-95ea824d46a7.png)


![image](https://user-images.githubusercontent.com/2114189/229422031-10f6b4a5-af76-40ee-8fa1-692112a9274f.png)

To avoid duplicated load of the same data in an HTTP request, we can set
a context cache to do that. i.e. Some pages may load a user from a
database with the same id in different areas on the same page. But the
code is hidden in two different deep logic. How should we share the
user? As a result of this PR, now if both entry functions accept
`context.Context` as the first parameter and we just need to refactor
`GetUserByID` to reuse the user from the context cache. Then it will not
be loaded twice on an HTTP request.

But of course, sometimes we would like to reload an object from the
database, that's why `RemoveContextData` is also exposed.

The core context cache is here. It defines a new context
```go
type cacheContext struct {
	ctx  context.Context
	data map[any]map[any]any
        lock sync.RWMutex
}

var cacheContextKey = struct{}{}

func WithCacheContext(ctx context.Context) context.Context {
	return context.WithValue(ctx, cacheContextKey, &cacheContext{
		ctx:  ctx,
		data: make(map[any]map[any]any),
	})
}
```

Then you can use the below 4 methods to read/write/del the data within
the same context.

```go
func GetContextData(ctx context.Context, tp, key any) any
func SetContextData(ctx context.Context, tp, key, value any)
func RemoveContextData(ctx context.Context, tp, key any)
func GetWithContextCache[T any](ctx context.Context, cacheGroupKey string, cacheTargetID any, f func() (T, error)) (T, error)
```

Then let's take a look at how `system.GetString` implement it.

```go
func GetSetting(ctx context.Context, key string) (string, error) {
	return cache.GetWithContextCache(ctx, contextCacheKey, key, func() (string, error) {
		return cache.GetString(genSettingCacheKey(key), func() (string, error) {
			res, err := GetSettingNoCache(ctx, key)
			if err != nil {
				return "", err
			}
			return res.SettingValue, nil
		})
	})
}
```

First, it will check if context data include the setting object with the
key. If not, it will query from the global cache which may be memory or
a Redis cache. If not, it will get the object from the database. In the
end, if the object gets from the global cache or database, it will be
set into the context cache.

An object stored in the context cache will only be destroyed after the
context disappeared.

* Add main aria landmark to templates
 * Adjust some titles to improve understanding of location in navigation

Contributed by @Forgejo

* Refactor `i18n` to `locale`

- Currently we're using the `i18n` variable naming for the `locale`
struct. This contains locale's specific information and cannot be used
for general i18n purpose, therefore refactoring it to `locale` makes
more sense.
- Ref: https://github.com/go-gitea/gitea/pull/20096#discussion_r906699200

* Update routers/install/install.go

- Resolves #14574
- Adds the necessary code to have pagination working in the forks list of
a repo. The code is mostly in par with the stars/watcher implementation.

There are multiple places where Gitea does not properly escape URLs that it is building and there are multiple places where it builds urls when there is already a simpler function available to use this.
    
This is an extensive PR attempting to fix these issues.

1. The first commit in this PR looks through all href, src and links in the Gitea codebase and has attempted to catch all the places where there is potentially incomplete escaping.
2. Whilst doing this we will prefer to use functions that create URLs over recreating them by hand.
3. All uses of strings should be directly escaped - even if they are not currently expected to contain escaping characters. The main benefit to doing this will be that we can consider relaxing the constraints on user names and reponames in future. 
4. The next commit looks at escaping in the wiki and re-considers the urls that are used there. Using the improved escaping here wiki files containing '/'. (This implementation will currently still place all of the wiki files the root directory of the repo but this would not be difficult to change.)
5. The title generation in feeds is now properly escaped.
6. EscapePound is no longer needed - urls should be PathEscaped / QueryEscaped as necessary but then re-escaped with Escape when creating html with locales Signed-off-by: Andrew Thornton <art27@cantab.net>

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Direct avatar rendering

This adds new template helpers for avatar rendering which output image
elements with direct links to avatars which makes them cacheable by the
browsers.

This should be a major performance improvment for pages with many avatars.

* fix avatars of other user's profile pages

* fix top border on user avatar name

* uncircle avatars

* remove old incomplete avatar selector

* use title attribute for name and add it back on blame

* minor refactor

* tweak comments

* fix url path join and adjust test to new result

* dedupe functions

* Add class to page content to unify top margin

Previously pages would individually set this margin but some didn't so
content would stick to the header without any space. Resolve this by
adding a new class that is added on all pages. The only place where we
remove this margin again is on the pages with menu or wrapper in the
header.

* fix admin notices

* fix team pages

* fix loading segment on gitgraph for arc-green

* fix last missing case

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

This commit improves templates readability, since all of them use consistent
indent with all template command blocks indented too.

1. Indents both HTML containers such as <div>, <p> and Go HTML template blocks
   such as {{if}} {{with}}

2. Cleans all trailing white-space

3. Adds trailing last line-break to each file

Merges repo/sidebar.tmpl with repo/header.tmpl and makes every repo page use
middleware.RepoRef() necessary to display information on this menu.

This is more inline with way GitHub looks like and feels much more natural and
in style with rest of the interface.