Limit number of entries to prefill from cache

Add paranoia exception catch in Linearizer

Some tables, like device_inbox, take a long time to query at startup for
the stream change cache prefills. This is likely because they are slower
growing streams and so are more fragmented on disk. For now, lets pull
fewer entries out to make startup quicker.

In future, we should add a better index to make it even faster.

Log which files we saved attachments to in the media_repository

Don't block messages sending on bumping presence

Linearize updates to membership via PUT /state/

Name linearizer's for better logs

This reverts commit b2850e62.

handlers/room_member: fix guest access check when joining rooms

Signed-off-by: Patrik Oldsberg <patrik.oldsberg@ericsson.com>

log call paths for resolve_state_group

add logging for all the places we call resolve_state_groups. my kingdom for a backtrace that actually works.