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>

templates/admin/dashboard.tmpl

@@ -61,6 +61,10 @@
 							<td>{{.locale.Tr "admin.dashboard.delete_generated_repository_avatars"}}</td>
 							<td class="text right"><button type="submit" class="ui green button" name="op" value="delete_generated_repository_avatars">{{svg "octicon-play"}} {{.locale.Tr "admin.dashboard.operation_run"}}</button></td>
 						</tr>
+						<tr>
+							<td>{{.locale.Tr "admin.dashboard.sync_repo_branches"}}</td>
+							<td class="text right"><button type="submit" class="ui green button" name="op" value="sync_repo_branches">{{svg "octicon-play"}} {{.locale.Tr "admin.dashboard.operation_run"}}</button></td>
+						</tr>
 					</tbody>
 				</table>
 			</form>