Drop several groups from the default user groups

Drops audio, cdrom, floppy, video, plugdev, netdev, scanner and bluetooth from the default groups to add to the first user created.

On modern systems, access control to devices is dynamic, and thus access to the relevant hardware is by default given to the currently physically logged-in user, and then access is revoked when they log out. These groups thus are unnecessary and possibly harmful (as they allow eavesdropping or modifying devices in use by other users). They can always be added by the admin if so desired.

Closes: #821424, #766914