Backport #27231 #27259 manually

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Co-authored-by: delvh <dev.lh@web.de>

The code was just copied&pasted, it causes problems now.

There are a lot (for every package) broken translations. eg:

```
# en-US
conda.documentation = For more information on the Conda registry, see 
<a target="_blank" rel="noopener noreferrer" href="%s">the documentation</a>.

# fr-FR (and many languages)
conda.documentation=Pour plus d'informations sur le registre Conda, voir 
<a target="_blank" rel="noopener noreferrer" href="https://docs.gitea.io/fr-fr/packages/conda/">la documentation</a>.
```


To resolve the problem fundamentally, use a general string, and trigger
the re-translating on Crowdin side.


And, it should really really really avoid introducing too much
copied&pasted code .......

Addition to
https://github.com/go-gitea/gitea/pull/24426#discussion_r1181261215

I updated all existing translations too because otherwise they would
show something like

> For more information on the Container registry, see [the
documentation](#).%!(EXTRA
string=https://docs.gitea.io/en-us/packages/container/)

---------

Co-authored-by: Giteabot <teabot@gitea.io>

This PR follows:
* #21986
* #22831

This PR also introduce customized HTML elements, which would also help
problems like:
* #17760
* #21429
* #21440

With customized HTML elements, there won't be any load-search-replace
operations, and it can avoid page flicking (which @silverwind cares a
lot).

Browser support:
https://developer.mozilla.org/en-US/docs/Web/API/Window/customElements

# FAQ

## Why the component has the prefix?

As usual, I would strongly suggest to add prefixes for our own/private
names. The dedicated prefix will avoid conflicts in the future, and it
makes it easier to introduce various 3rd components, like GitHub's
`relative-time` component. If there is no prefix, it's impossible to
introduce another public component with the same name in the future.

## Why the `custcomp.js` is loaded before HTML body? The `index.js` is
after HTML body.

Customized components must be registered before the content loading.
Otherwise there would be still some flicking.

`custcomp.js` should have its own dependencies and should be very light,
so it won't affect the page loading time too much.

## Why use `data-url` attribute but not use the `textContent`?

According to the standard, the `connectedCallback` occurs on the
tag-opening moment. The element's children are not ready yet.

## Why not use `{{.GuessCurrentOrigin $.ctx ...}}` to let backend decide
the absolute URL?

It's difficult for backend to guess the correct protocol(scheme)
correctly with zero configuration. Generating the absolute URL from
frontend can guarantee that the URL is 100% correct -- since the user is
visiting it.

# Screenshot

<details>

![image](https://user-images.githubusercontent.com/2114189/218256757-a267c8ba-3108-4755-9ae5-329f1b08f615.png)

</details>

This PR adds a [Conda](https://conda.io/) package registry.