Sync branches into databases (#22743)

Related #14180
Related #25233 
Related #22639
Close #19786
Related #12763 

This PR will change all the branches retrieve method from reading git
data to read database to reduce git read operations.

- [x] Sync git branches information into database when push git data
- [x] Create a new table `Branch`, merge some columns of `DeletedBranch`
into `Branch` table and drop the table `DeletedBranch`.
- [x] Read `Branch` table when visit `code` -> `branch` page
- [x] Read `Branch` table when list branch names in `code` page dropdown
- [x] Read `Branch` table when list git ref compare page
- [x] Provide a button in admin page to manually sync all branches.
- [x] Sync branches if repository is not empty but database branches are
empty when visiting pages with branches list
- [x] Use `commit_time desc` as the default FindBranch order by to keep
consistent as before and deleted branches will be always at the end.

---------

Co-authored-by: Jason Song <i@wolfogre.com>

routers/web/repo/pull.go

@@ -1493,7 +1493,7 @@ func UpdatePullRequestTarget(ctx *context.Context) {
 				"error":      err.Error(),
 				"user_error": errorMessage,
 			})
-		} else if models.IsErrBranchesEqual(err) {
+		} else if git_model.IsErrBranchesEqual(err) {
 			errorMessage := ctx.Tr("repo.pulls.nothing_to_compare")
 
 			ctx.Flash.Error(errorMessage)