The only "database type storage plugin" is SlurmDBD, so refer
to it directly.

Mention the default database name in slurmdbd.conf if StorageHost
is not explicitly set.

Bug 5270.

Leave the underlying --launcher-opts in place.

Looks a bit busier, but this is just due to moving code in a tabstop.

This removes the -B option to slurmctld as well, update
the man page as appropriate.

This was developed after the commit that follows, but the order was
switched around to make sure both commits compile cleanly.

All of these select_g_select_jobinfo_get/set() calls are no-ops.

Also remove a call to SELECT_JOBDATA_IONODES which is a no op.