Playwright testing for commit diffs

includes:

- easier repo declaration for playwright tests by @Gusted
- full backend build for pushing Git repos by @Gusted
- playwright testing (which fails with the current diff algorithm, but
  passes with the new)
- disable eslint rule for conditional expect, because it defeats the
  purpose (working around it would result in much more complex test code
  in our cases)

tests/e2e/debugserver_test.go

@@ -24,7 +24,8 @@ func TestDebugserver(t *testing.T) {
 	done := make(chan os.Signal, 1)
 	signal.Notify(done, syscall.SIGINT, syscall.SIGTERM)
 
-	onGiteaRun(t, func(*testing.T, *url.URL) {
+	onForgejoRun(t, func(*testing.T, *url.URL) {
+		defer DeclareGitRepos(t)()
 		fmt.Println(setting.AppURL)
 		<-done
 	})