Log Message:
snac: update to 2.48. Changes:

A new instance page, that shows all posts by users in the same instance
(like the public instance timeline, but interactive). This will help
building communities.

Follower-only replies to unknown users are not shown in timelines.

Added verification of metadata links: if the linked page contains a
link back to the snac user with a rel="me" attribute, it's marked
as verified.

Added a new server-level configuration parameter: `min_account_age`. If
this value (in seconds) is set in `server.json`, any activity coming
from accounts that were created newer than that will be discarded. This
can be used to mitigate spam.

Added a profile-page relation to links in webfinger responses
(contributed by khm).

Fixed some regressions and a crash.