L2CAP: Implement configuration negotiation to support mandatory/optional

use of ERTM

* To support mandatory use of ERTM, gd L2CAP should initiate
  disconnection when remote does not support/wish or attempts to
  configure to Basic Mode.
* Add ENHANCED_RETRANSMISSION_OPTION in RetransmissionAndFlowControlMode
  to specified mandatory and optional.
* Add FAIL_REMOTE_NOT_SUPPORT to indicate upper layer of connection
  channel fail due to remote no supporting ERTM when using mandatory
  ERTM.
* Add cert test cases:
    test_config_respond_basic_mode_when_using_mandatory_ertm
    test_config_request_basic_mode_when_using_mandatory_ertm
    test_respond_not_support_ertm_when_using_mandatory_ertm

Test: cert/run --host
Bug: 151049713
Change-Id: Id383a113f648acb1061668bb24f49256afb9bd6f