Merge changes I9b116e04,Ib00d354a,I96e58238,Icd4f61ae,Ibd713dd5, ...

* changes:
  Move some acl specific setup from devctl to btm_acl
  Remove last vestiges of link_policy from dm
  Associate role management with ACL, not device management
  Remove BTA_DM_LINK_POLICY_SETTINGS & friends
  Encapsulate all default policy setting inside ACL
  Make sniff mode blocking/unblocking look like role switch
  Remove l2cu_get_conn_role
  L2CA_SetDesireRole literally changes nothing
  L2CAP_DESIRED_LINK_ROLE is always "master"
  Don't use L2CA_SetDesireRole to set policy