Fixes#9067. Adds a delete button that appears on hover over an
uploaded profile photo; clicking it opens a confirm modal and, on
accept, clears the stored photo so the generated fallback avatar is
shown again. A new :delete-profile-photo RPC schedules the old
storage object for garbage collection and sets photo-id to null.
Signed-off-by: moorsecopers99 <patellscott18@gmail.com>
Co-authored-by: Andrey Antukh <niwi@niwi.nz>