delvh e10ba5e5e0
Rename `Sync2` -> `Sync` ()
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
```
..
db.go Replace `interface{}` with `any` ()
db_test.go Rename `Sync2` -> `Sync` ()
hash.go Use minio/sha256-simd for accelerated SHA256 ()
main_test.go Implement FSFE REUSE for golang files ()
tests.go Rename `Sync2` -> `Sync` ()