This resolves a problem I encountered while updating gitea from 1.20.4
to 1.21. For some reason (correct or otherwise) there are some values in
`repository.size` that are NULL in my gitea database which cause this
migration to fail due to the NOT NULL constraints.
Log snippet (excuse the escape characters)
```
ESC[36mgitea |ESC[0m 2023-12-04T03:52:28.573122395Z 2023/12/04 03:52:28 ...ations/migrations.go:641:Migrate() [I] Migration[263]: Add git_size and lfs_size columns to repository table
ESC[36mgitea |ESC[0m 2023-12-04T03:52:28.608705544Z 2023/12/04 03:52:28 routers/common/db.go:36:InitDBEngine() [E] ORM engine initialization attempt #3/10 failed. Error: migrate: migration[263]: Add git_size and lfs_size columns to repository table failed: NOT NULL constraint failed: repository.git_size
```
I assume this should be reasonably safe since `repository.git_size` has
a default value of 0 but I don't know if that value being 0 in the odd
situation where `repository.size == NULL` has any problematic
consequences.
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
```
releated to #21820
- Split `Size` in repository table as two new colunms, one is `GitSize`
for git size, the other is `LFSSize` for lfs data. still store full size
in `Size` colunm.
- Show full size on ui, but show each of them by a `title`; example:
- Return full size in api response.
---------
Signed-off-by: a1012112796 <1012112796@qq.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: DmitryFrolovTri <23313323+DmitryFrolovTri@users.noreply.github.com>
Co-authored-by: Giteabot <teabot@gitea.io>
