rollback register/auth changes

WIP: try to extend XMPP rather than to modify it

purpose:
add this functions while keeping the old ones work:
1. authenticate user with phone number/email
2. register with phone number/email

take:
1. revert the changes to thess files:
  crysasl.erl
  crysasl_digest.erl
  crysasl_scram.erl
  mod_register
2. implement
  cyrsasl_scram_aft
  mod_register_aft