acl: implement a centralized ACL output mechanism for HAs and ACLs.

named_acl.c (which is really a named_ha) now uses ast_ha_output.

I've also updated main/manager.c to output the actual ACL on "manager
show user <username>" if one is set.  If this works then we can add
similar to other modules as required.

Change-Id: I0ec9876a90dddd379c80ec078d48e3ee6991eb0f