use user id in noreply emails (#36550)

This implements id based hidden emails in format of
`user+id@NoReplyAddress`

resolves: https://github.com/go-gitea/gitea/issues/33471

---

The change is not breaking however it is recommended for users to move
to this newer type of no reply address

---------

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

tests/integration/editor_test.go

@@ -258,7 +258,7 @@ func testEditorWebGitCommitEmail(t *testing.T) {
 		t.Run("DefaultEmailKeepPrivate", func(t *testing.T) {
 			defer tests.PrintCurrentTest(t)()
 			paramsForKeepPrivate["commit_email"] = ""
-			resp1 = makeReq(t, linkForKeepPrivate, paramsForKeepPrivate, "User Two", "user2@noreply.example.org")
+			resp1 = makeReq(t, linkForKeepPrivate, paramsForKeepPrivate, "User Two", "user2+2@noreply.example.org")
 		})
 		t.Run("ChooseEmail", func(t *testing.T) {
 			defer tests.PrintCurrentTest(t)()