Issue #2219783 by almaudoh: Implement hook_sms_validate() to streamline sms number validation process

Factor out sms_test_gateway_send() to sms_test_gateway_result() for getting results of past sent messages.

Issue #2374761 by Joanna_Kisaakye: Fixed Raw html instead of a link in please confirm number message.

Issue #2351575 by Joanna_Kisaakye, almaudoh: Added user ID of the author and recipient of the message to sms_track.

Issue #1477794 by Joanna_Kisaakye, atlea: Fixed Notice: Undefined index: gateway in sms_send_form_validate().

Issue #2185179 by almaudoh, JulienF: Fixed Remove Mobile Number Rule integration is not working correctly.

Issue #1915022 by almaudoh, ekes | DaveyM: Fixed No phone number validation on user registration form.