Add a new :guess action for crowbar_pacemaker_sync_mark

This will guess the right action based on the name; this is something we
were doing to guess the mark, but we can go further and actually guess
the action too.

This is the default action.
Remove name of cookbook from synchronization marks

This is actually not useful because the name of the marks have to be
unique (otherwise, the various crowbar_pacemaker_sync_mark resources in
different cookbooks will conflict).