Enable echo protocol in lighting app for secure channel test

[yufengwangca]

Problem

provide test interface (API) to test section 4.13 (CRMP) using lighting-app as the accessory.

Provide a way to send Message with R flag set, verify receiver to send back an acknowledgment. If R flag is not set , message is unreliable and do not expect ACK from receiver.
Verify if ACK msg contains A flag. When set, the Acknowledged Message Counter field SHALL be present and valid
Create unreliable message to piggyback ACKs.
Detect duplicate Messages, Parse the received message contents per section 4.3.3.

Proposed Solution

Enable echo protocol in lighting app for secure channel test