Check REQUEST_COMPANION_SELF_MANAGED permission in CDM

Check if the caller holds REQUEST_COMPANION_SELF_MANAGED permission when
processing an AssociationRequest for a "self-managed" association in
CDM.

Introduce RolesUtils and PermissionsUtils utility classes.

Bug: 194301022
Test: atest CompanionDeviceManagerTest
Change-Id: Ia359f912fd28950a1251492f7e7b8452852008b6