Explicitly mark systemd unit as Type=simple

Bees does not fork, so let's not rely on systemd defaults.

scripts/beesd@.service

@@ -3,6 +3,7 @@ Description=Bees - Best-Effort Extent-Same, a btrfs deduplicator daemon: %i
 After=local-fs.target
 
 [Service]
+Type=simple
 ExecStart=/usr/sbin/beesd %i
 Nice=19
 IOSchedulingClass=idle