Implement support for Requester as Event Initiator and Responder as Event Recipient

[steven-bellock]

• Requester support for encapsulated GET_SUPPORTED_EVENT_TYPES.
  • Encapsulated SUPPORTED_EVENT_TYPES support for Requester #3173
• Requester support for encapsulated SUBSCRIBE_EVENT_TYPES.
  • Encapsulated SUBSCRIBE_EVENT_TYPES support for Requester #3218
• Requester support for SEND_EVENT.
  • SEND_EVENT support for Requester #3233
• Responder support for encapsulated GET_SUPPORTED_EVENT_TYPES.
• Responder support for encapsulated SUBSCRIBE_EVENT_TYPES.
• Responder support for SEND_EVENT.
  • SEND_EVENT support for Responder  #3253

[steven-bellock]

This also includes a new API for the Responder encapsulated flow. This applies to the event flow as well as encapsulated GET_ENDPOINT_INFO.