s3-passdb: Python wrapper for passdb

s3-passdb: Python wrapper for passdb

- Added Groupmap python wrapper
- Added passdb methods

   getgrsid, getgrgid, getgrnam
   create_dom_group, delete_dom_group
   add_group_mapping_entry, update_group_mapping_entry, delete_group_mapping_entry
   enum_group_mapping, enum_group_members
   add_groupmem, del_groupmem
   create_alias, delete_alias
   get_aliasinfo, set_aliasinfo
   add_aliasmem, del_aliasmem, enum_aliasmem
   get_account_policy, set_account_policy
   search_groups, search_aliases

Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>
Signed-off-by: Andrew Bartlett <abartlet@samba.org>