Fix lock services not stopping after waking up
Run in session.slice

From systemd.special(7):

> session.slice
>   All essential services and applications required for the session should use
>   this slice. These are services that either cannot be restarted easily or where
>   latency issues may affect the interactivity of the system and applications.
>   This includes the display server, screen readers and other services such as
>   DBus or XDG portals. Such services should be configured to be part of this
>   slice by adding Slice=session.slice to their unit files.
Include a changelog
Improve the README
Fix bogus log message
Translate session unlock event to unlock.target
Improve the README a bit more
Notify systemd when we've initialised successfully
Use go-systemd for service management
Make logging format systemd-friendly
Improve error handling and logging
Tidy up infinite loop
Configure pre-commit hooks
Run linting and tests in CI

Some wording improvements and convert it to markdown.
Update project URL in service file
Update build instructions
Fix mixup in Makefile