mcp: Implement Media Control Profile

Architecture-wise it defines the Mcs Manager as an
entry point for registering Mcs Service instances.
Most of the service related API is not exposed in the
IPC mechanism since is used only internally.

Bug: 150670922
Tag: #feature
Test: manual testing
Sponsor: jpawlowski@
Merged-In: I414af987250807c2c8b6d94213ef044035f6bad6
Change-Id: I414af987250807c2c8b6d94213ef044035f6bad6