Prevent hang in git cat-file if repository is not a valid repository and other fixes (#17991)

This PR contains multiple fixes. The most important of which is:

* Prevent hang in git cat-file if the repository is not a valid repository 
    
    Unfortunately it appears that if git cat-file is run in an invalid
    repository it will hang until stdin is closed. This will result in
    deadlocked /pulls pages and dangling git cat-file calls if a broken
    repository is tried to be reviewed or pulls exists for a broken
    repository.

    Fix #14734
    Fix #9271
    Fix #16113

Otherwise there are a few small other fixes included which this PR was initially intending to fix:

* Fix panic on partial compares due to missing PullRequestWorkInProgressPrefixes
* Fix links on pulls pages  due to regression from #17551 - by making most /issues routes match /pulls too - Fix #17983
* Fix links on feeds pages due to another regression from #17551 but also fix issue with syncing tags - Fix #17943
* Add missing locale entries for oauth group claims
* Prevent NPEs if ColorFormat is called on nil users, repos or teams.

modules/indexer/code/elastic_search.go

@@ -247,6 +247,11 @@ func (b *ElasticSearchIndexer) addDelete(filename string, repo *repo_model.Repos
 func (b *ElasticSearchIndexer) Index(repo *repo_model.Repository, sha string, changes *repoChanges) error {
 	reqs := make([]elastic.BulkableRequest, 0)
 	if len(changes.Updates) > 0 {
+		// Now because of some insanity with git cat-file not immediately failing if not run in a valid git directory we need to run git rev-parse first!
+		if err := git.EnsureValidGitRepository(git.DefaultContext, repo.RepoPath()); err != nil {
+			log.Error("Unable to open git repo: %s for %-v: %v", repo.RepoPath(), repo, err)
+			return err
+		}
 
 		batchWriter, batchReader, cancel := git.CatFileBatch(git.DefaultContext, repo.RepoPath())
 		defer cancel()