ROX-25719: Runtime control channel

[ovalenti]

Description

Collector needs a new grpc API to manage its configuration dynamically, in particular for runtime-filtering.

We propose an approach similar to the iSensor service, where a bi-directional stream is opened on top of a single grpc method. Then multiple object types can flow in each direction by making them part of a oneof list containing all off them.

The main messages should be aimed at:

• exchange capabilities.
• set the initial filtering and update it at any time.
• retrieve statistics and troubleshooting information.

Checklist

• Investigated and inspected CI test results
• Updated documentation accordingly

Automated testing

• Added unit tests
• Added integration tests
• Added regression tests