See also:
https://daniel.haxx.se/blog/2023/01/08/copyright-without-years/
https://hynek.me/til/copyright-years/

* First draft of unread line feature.

* Minor visual fix.

* Removed unnecessary ternary operator.

* Extended unread line functionality to work on minimised window or focusing another window.

* Fix for unread line not showing when last read message is hidden.

* Minor performance improvement. Fix for misbehaving event2order DB at application start.

* Fix for possible performance issues when user has joined a large number of rooms.

* Fix for breaking macos and clazy builds.

* Changed on windows focus function to refresh unread line if room is unread.

* Unread line is removed when user sends a message.

* Linting.

* Fixed unread line to work in standalone room windows.

* Switch isRoomUnread for index 0.

* Merged try/catch blocks.

* Fix for crash on opening a room invite.

* Call fullyReadEventId function when used instead of storing it and passing it through.

* Function that was meant to sync the unread line was relying on an async function, oops.

* Linting again.

* More linting...

* Minor changes.

We share all keys with our devices and ones created by us to other
users.

Does not fix the read status yet, for that we need to compare read
receipts for all events after the last visible event.

We don't get notified for every message. Sometimes we only get a read
receipt for the newest message, which means old read receipts accumulate
in the database. This least to some considerable CPU overhead, when
checking if the timeline should be notified for new read receipts.
Instead just always notify, since that has far less overhead in the
worst case and doesn't need complicated cache cleanup.

The old pending_receipts db is not removed for now. It should still have
minimal storage overhead and we don't have a good mechanism for cache
format upgrades atm.