First version of the App2App Messaging API

Jira issue: WP-218
Fixed reference to connect request callback.

Jira issue: WP-696
Added app2app support for peer mode

Changed app2app to dynamic service and added state listeners. Now the
PZP will register the app2app service only if the PZH is disconnected.

Jira issue: WP-681
Allow creator reconnect and detach.

Jira issue: WP-799
Changed channel reclaim to explicit parameter

Jira issue: WP-799
App2App move to newer repository