[NEXUS-5490] Automatically enable Rut Auth realm when capability is enabled

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5490] Add IT verifying that when authentication capability is created/enabled, Ruth Auth realm is automatically added to the list of configured realms

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>