docs: acl: Convert to 'rst'

docs: acl: Convert to 'rst'

The only special bit about the 'acl' page was the inclusion of the
objects and permissions tables. We can do that by the '.. raw::'
directive.

One reference from 'aclpolkit.rst' needed to be updated to go with the
new header anchor naming.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>