Report health messages via log events

[thompson-tomo]

We should introduce a way to inform an agent to send health changes via otlp as log events which follow semantic conventions.

This setting should not stop the sending of health data to the control server via opamp by default however it should be possible to stop just the sending of health data via opamp without stopping otlp.

What this might look like is:

• A new ServerCapabilities AcceptsHealth which controls if health is sent via opamp
• within the ConnectionSettingsOffers message their should be a field to indicate if events are supported.

[tigrannajaryan]

Why do we need anything about it in OpAMP? If the agent wants to send its health status via OTLP logs the agent can do it independently from specific native OpAMP setting. If you need that behavior to be controlled via OpAMP then you can send that as a configuration option to the agent using OpAMP's remote configuration capabilities (of course this implies the agent is able to accept remote configuration and has a setting that remote configuration that enables/disables "health-via-logs" behavior of the agent).