External function
tool_mobile::tool_mobile_get_plugins_supporting_mobile is now available
via AJAX for not logged users.
When called via AJAX without a user session the function will return
only auth plugins.
We din't call it SSO because:
- SSO usually requires a 3rd party for authentication
- SSO term is already used in tool_mobile when supporting using auth methods like CAS or Shibboleth
Juan Leyva