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.

services/pull/pull.go

@@ -746,7 +746,8 @@ func GetIssuesLastCommitStatus(issues models.IssueList) (map[int64]*models.Commi
 		if !ok {
 			gitRepo, err = git.OpenRepository(issue.Repo.RepoPath())
 			if err != nil {
-				return nil, err
+				log.Error("Cannot open git repository %-v for issue #%d[%d]. Error: %v", issue.Repo, issue.Index, issue.ID, err)
+				continue
 			}
 			gitRepos[issue.RepoID] = gitRepo
 		}