clean up command line args in ipa-delradiusclient

  get_radius_profile_by_uid
  add_radius_profile
  update_radius_profile
  delete_radius_profile
  find_radius_profiles

Rewrite command line arg handling, now support pair entry, interactive
mode with auto completion, reading pairs from a file, better handling
of mandatory values, better help, long arg names now match attribute
name in pairs

Establish mappings for all attributes and names used in clients and
profiles

Add notion of containers to radius clients and profiles in LDAP

Move common code, variables, constants, and strings into the files
radius_client.py, radius_util.py, ipautil.py to eliminate redundant
elements which could get out of sync if modified and to provide access
to other code which might benefit from using these items in the
future.

Add utility functions:
  format_list()
  parse_key_value_pairs()

Add utility class:
  AttributeValueCompleter

Unify attribute usage in radius ldap schema