This PR contains new source for antenna posts, which is a list of instance hostnames to process all posts from.
Using this mode, a user can filter for keywords on an instance wide basis.
This change includes a new antenna source called `instances` and a new database column in the `antenna` table called `instances` to store the instance names.
On the antenna editor, there's also an "Add an instance" finder dialog to allow users to search through the known instance hostnames.
Co-authored-by: Kaity A <supakaity@blahaj.zone>
Reviewed-on: https://codeberg.org/calckey/calckey/pulls/9604
Co-authored-by: Kaity A <supakaity@noreply.codeberg.org>
Co-committed-by: Kaity A <supakaity@noreply.codeberg.org>