Add "Update Branch" button to Pull Requests (#9784)

* add Divergence

* add Update Button

* first working version

* re-use code

* split raw merge commands and db-change functions (notify, cache, ...)

* use rawMerge (remove redundant code)

* own function to get Diverging of PRs

* use FlashError

* correct Error Msg

* hook is triggerd ... so remove comment

* add "branch2" to "user2/repo1" because it unit-test "TestPullView_ReviewerMissed" use it but dont exist jet :/

* move GetPerm to IsUserAllowedToUpdate

* add Flash Success MSG

* imprufe code
- remove useless js chage

* fix-lint

* TEST: add PullRequest ID:5
Repo: user2/repo1
Base: branch1
Head: pr-to-update

* correct comments

* make PR5 outdated

* fix Tests

* WIP: add pull update test

* update revs

* update locales

* working TEST

* update UI

* misspell

* change style

* add 1s delay so rev exist

* move row up (before merge row)

* fix lint nit

* UI remove divider

* Update style

* nits

* do it right

* introduce IsSameRepo

* remove useless check

Co-authored-by: Lauris BH <lauris@nix.lv>

routers/routes/routes.go

@@ -855,6 +855,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 			m.Get(".patch", repo.DownloadPullPatch)
 			m.Get("/commits", context.RepoRef(), repo.ViewPullCommits)
 			m.Post("/merge", context.RepoMustNotBeArchived(), reqRepoPullsWriter, bindIgnErr(auth.MergePullRequestForm{}), repo.MergePullRequest)
+			m.Post("/update", repo.UpdatePullRequest)
 			m.Post("/cleanup", context.RepoMustNotBeArchived(), context.RepoRef(), repo.CleanUpPullRequest)
 			m.Group("/files", func() {
 				m.Get("", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.ViewPullFiles)