Roles support no longer needed

Roles support in uif_plus is no longer needed in this module as it is supported directly in uif as of 7.x-1.3. The previous implementation of roles (as update hook) was not good, as roles should be included in the (one) user_save() call per import as per #1701920: Roles get assigned after user creation is finished this causes a problem with rule "After saving a new user account"