[MODERATION] user blocking

- Add the ability to block a user via their profile page.
- This will unstar their repositories and visa versa.
- Blocked users cannot create issues or pull requests on your the doer's repositories (mind that this is not the case for organizations).
- Blocked users cannot comment on the doer's opened issues or pull requests.
- Blocked users cannot add reactions to doer's comments.
- Blocked users cannot cause a notification trough mentioning the doer.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/540
(cherry picked from commit 687d852480)
(cherry picked from commit 0c32a4fde5)
(cherry picked from commit 1791130e3c)

models/activities/action.go

@@ -580,7 +580,7 @@ func NotifyWatchers(ctx context.Context, actions ...*Action) error {
 
 		if repoChanged {
 			// Add feeds for user self and all watchers.
-			watchers, err = repo_model.GetWatchers(ctx, act.RepoID)
+			watchers, err = repo_model.GetWatchersExcludeBlocked(ctx, act.RepoID, act.ActUserID)
 			if err != nil {
 				return fmt.Errorf("get watchers: %w", err)
 			}