-some modules will not be available during runtime, due to
external dependencies.
-these modules can now be marked optional.
-loading of these optional modules will be attempted and if
they are not available, wp will recover and will not be
terminated.
This copies the logic of media-session's logind module and allows
the bluez monitor to be active in only one user session at a time.
This is especially useful to avoid interference between the gdm
session and the actual user session, which momentarily both have
wireplumber running when logging in/out.
Fixes#54
After all, we can just load multiple lua config files/directories
from a single .conf file and so have both styles available for the
user to choose at runtime
