It should be possible to compress the data stream between agents and principal

[jannfis]

In some environments, network traffic is more costly than CPU cycles. Thus, it should be possible to turn on optional compression of the data streams exchanged over the gRPC service between the principal and the agent.

Compression should be switchable on a per-agent basis, and be requested by the agent during connection setup. In a later point in time, we might want to have a switch to enforce compression on the principal's side.