`models` does far too much. In particular it handles all `UserSignin`.

It shouldn't be responsible for calling LDAP, SMTP or PAM for signing in.

Therefore we should move this code out of `models`.

This code has to depend on `models` - therefore it belongs in `services`.

There is a package in `services` called `auth` and clearly this functionality belongs in there.

Plan:

- [x] Change `auth.Auth` to `auth.Method` - as they represent methods of authentication.
- [x] Move `models.UserSignIn` into `auth`
- [x] Move `models.ExternalUserLogin`
- [x] Move most of the `LoginVia*` methods to `auth` or subpackages
- [x] Move Resynchronize functionality to `auth`
  - Involved some restructuring of `models/ssh_key.go` to reduce the size of this massive file and simplify its files.
- [x] Move the rest of the LDAP functionality in to the ldap subpackage
- [x] Re-factor the login sources to express an interfaces `auth.Source`?
  - I've done this through some smaller interfaces Authenticator and Synchronizable - which would allow us to extend things in future
- [x] Now LDAP is out of models - need to think about modules/auth/ldap and I think all of that functionality might just be moveable
- [x] Similarly a lot Oauth2 functionality need not be in models too and should be moved to services/auth/source/oauth2
  - [x] modules/auth/oauth2/oauth2.go uses xorm... This is naughty - probably need to move this into models.
  - [x] models/oauth2.go - mostly should be in modules/auth/oauth2 or services/auth/source/oauth2 
- [x] More simplifications of login_source.go may need to be done
- Allow wiring in of notify registration -  *this can now easily be done - but I think we should do it in another PR*  - see #16178 
- More refactors...?
  - OpenID should probably become an auth Method but I think that can be left for another PR
  - Methods should also probably be cleaned up  - again another PR I think.
  - SSPI still needs more refactors.* Rename auth.Auth auth.Method
* Restructure ssh_key.go

- move functions from models/user.go that relate to ssh_key to ssh_key
- split ssh_key.go to try create clearer function domains for allow for
future refactors here.

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

One of the reasons why #16447 was needed and why #16268 was needed in
the first place was because it appears that editing ldap configuration
doesn't get tested.

This PR therefore adds a basic test that will run the edit pipeline.

In doing so it's now clear that #16447 and #16268 aren't actually
solving #16252. It turns out that what actually happens is that is that
the bytes are actually double encoded.

This PR now changes the json unmarshal wrapper to handle this double
encode.

Fix #16252

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

Co-authored-by: 6543 <6543@obermui.de>

* Accept multiple SSH keys in single LDAP SSHPublicKey attribute

Fix #13984

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

* Replace more icons with SVG

- Replace remaining icons on admin page with SVG
- Fix vertical menu background on arc-green
- Minor improvments to frontpage repo search
- More icon replacements here and there

* fix integration

* whitespace tweak

* add comment

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

* Remove obsolete change of email on profile page

The change email on the account profile page is out-of-date
and unnecessary.

Changing email should be done using the account page.

Fix #13336

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

* Refactor Cron and merge dashboard tasks

* Merge Cron and Dashboard tasks
* Make every cron task report a system notice on completion
* Refactor the creation of these tasks
* Ensure that execution counts of tasks is correct
* Allow cron tasks to be started from the cron page

* golangci-lint fixes

* Enforce that only one task with the same name can be registered

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

* fix name check

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

* as per @guillep2k

* as per @lafriks

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

* Add git.CommandContext variants

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

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

* Add restricted user filter to LDAP authentification

* Fix unit test cases

* Change graceful to use a singleton obtained through GetManager instead of a global.
* Graceful: Make TestPullRequests shutdownable
* Graceful: Make the cron tasks graceful
* Graceful: AddTestPullRequest run in graceful ctx
* Graceful: SyncMirrors shutdown
* Graceful: SetDefaultContext for Xorm to be HammerContext
* Avoid starting graceful for migrate commands and checkout
* Graceful: DeliverHooks now can be shutdown
* Fix multiple syncing errors in modules/sync/UniqueQueue &  Make UniqueQueue closable
* Begin the process of making the repo indexer shutdown gracefully

* Fix data race in testlogger

* Update git_helper_for_declarative_test.go

Signed-off-by: Tamal Saha <tamal@appscode.com>

* Fix issue where ecdsa and other key types are not synced from LDAP authentication provider fixes #5092

* integrations/auth_ldap_test.go: Add Hermes Conrad new ecdsa-sha2-nistp256 publickey fingerprint

* integrations/auth_ldap_test.go: Use ssh-keygen -lf <filename> -E sha256

* Add LDAP Key Synchronization feature

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Add migration: add login source id column for public_key table

* Only update keys if needed

* Add function to only list pubkey synchronized from ldap

* Only list pub ssh keys synchronized from ldap. Do not sort strings as ExistsInSlice does it.

* Only get keys belonging to current login source id

* Set default login source id to 0

* Some minor cleanup. Add integration tests (updete dep testify)

* Add LDAP service for tests

* Add LDAP login source and test user sign-in

* Add checks to test if user data is correct

* Add LDAP user sync test

* Add failed user sign-in test