Migrate libbeat agent management to the agent V2 control protocol

[cmacknz]

The existing agent V1 control protocol implementation is implemented in the libbeat management package: https://github.com/elastic/beats/tree/main/x-pack/libbeat/management. Migrate libbeat management package to the V2 protocol client. This should automatically convert any beat using the management package to run under agent to the V2 protocol.

Acceptance criteria:

• All existing unit and integration tests continue to pass.
• All existing agent E2E tests continue to pass.
• All existing beat authors are notified of the change, especially those that do not exist is the beat repository like APM server and cloudbeat.

Note This change cannot be merged until the elastic agent server side changes are complete and merged to the agent's main branch.

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)