Replace #6312
Help #5833
Wiki solution for #639

The xorm `Sync2` has already been deprecated in favor of `Sync`,
so let's do the same inside the Gitea codebase.

Command used to replace everything:
```sh
for i in $(ag Sync2 --files-with-matches); do vim $i -c ':%sno/Sync2/Sync/g' -c ':wq'; done
```

Change all license headers to comply with REUSE specification.

Fix #16132

Co-authored-by: flynnnnnnnnnn <flynnnnnnnnnn@github>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

There are too many files in `models/migrations` folder so that I split
them into sub folders.

* Move access and repo permission to models/perm/access

* fix test

* fix git test

* Move functions sequence

* Some improvements per @KN4CK3R and @delvh

* Move issues related code to models/issues

* Move some issues related sub package

* Merge

* Fix test

* Fix test

* Fix test

* Fix test

* Rename some files

* Move unit into models/unit/

* Rename unit.UnitType as unit.Type

* Fix various doc, user-facing, and source comment typos

Found via `codespell -q 3 -S ./options/locale,./vendor -L ba,pullrequest,pullrequests,readby`

* chore: rewrite format.

* chore: update format

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* chore: update format

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* chore: Adjacent parameters with the same type should be grouped together

* chore: update format.

* Fix bug on migration 111

* Check reviews when migrating v111

* Fix bug

* Fix commit

* Fix bug preventing transfer to private organization

The code assessing whether a private organization was visible to a user before
allowing transfer was incorrect due to testing membership the wrong way round

This PR fixes this issue and renames the function performing the test to be
clearer.

Further looking at the API for transfer repository - no testing was
performed to ensure that the acting user could actually see the new
owning organization.

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

* change IsUserPartOfOrg everywhere

* Refactor: Remove Dependencys from Migration v111

* Update models/migrations/v111.go

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

* Issue with Migration rule v111

I was facing some issues with migration rule v111

* Update v111.go

Fix pgsql test cases

Co-authored-by: Antoine GIRARD <sapk@users.noreply.github.com>

* Possibility to not use whitelist but allow anyone with write access

* fix existing test

* rename migration function

* Try to give a better name for migration step

* Clear settings if higher level setting is not set

* Move official reviews to db instead of counting approvals each time

* migration

* fix

* fix migration

* fix migration

* Remove NOT NULL from EnableWhitelist as migration isn't possible

* Fix migration, reviews are connected to issues.

* Fix SQL query issues in GetReviewersByPullID.

* Simplify function GetReviewersByIssueID

* Handle reviewers that has been deleted

* Ensure reviews for test is in a well defined order

* Only clear and set official reviews when it is an approve or reject.