MAJOR: acl: store the ACL argument types in the ACL keyword declaration

MAJOR: acl: store the ACL argument types in the ACL keyword declaration

The types and minimal number of ACL keyword arguments are now stored in
their declaration. This will allow many more fantasies if some ACL use
several arguments or types.

Doing so required to rework all ACL keyword declarations to add two
parameters. So this was a good opportunity for a general cleanup and
to sort all entries in alphabetical order.

We still have two pending issues :
  - parse_acl_expr() checks for errors but has no way to report them to
    the user ;
  - the types of some arguments are still not resolved and kept as strings
    (eg: ARGT_FE/BE/TAB) for compatibility reasons, which must be resolved
    in acl_find_targets()