Filter by domain where possible

[shephirt]

Summary

I would like to have a filter by domain option wherever possible.
Similar to the Domain filter option in the Alias section, it would be highly beneficial to have the same filter in the Mailbox section.

There might be additional areas where this filter could be useful, but most noticable will be in the mailbox section.

Motivation

When having a large number of mailboxex in combination with different domains, a filter by domain option would be highly beneficial. Especially if you would like to make changes to all mailboxes from a specific domain.

Additional context

Alias section

Mailbox section