* Properly generate ref URLs

Tags used to not generate correct URLs (src/branch/tags/1.0.0 instead of
src/tags/1.0.0).

Also cleans up some code around it with the created helper functions.

* Fix formatting and create migration

* Add copyright head to utils_test

* Use a raw query for the ref migration

* Remove semicolon

* Quote column and table names in migration SQL

* Change || to CONCAT, since MSSQL does not support ||

* Make migration engine aware

* Add missing import

* Move ref EndName and URL to the issue service

* Fix tests

* Add test for commit refs

* Update issue.go

* Use the right command for building JavaScript bundles

* Prepare for merge

* Check for refs/* before prepending in migration

* Update services/issue/issue_test.go

* Update modules/git/utils_test.go

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