Add inputs compatibility status

[jillguyonnet]

A new agent.version condition is introduced in package manifests in order to specify the minimum compatible version of Elastic Agent version. Based on this, Fleet will report the minimum compatible agent version (if any) in the agent policy.

The output of elastic-agent status and state.yaml file in diagnostics should report any incompatibility in order to provide better visibility.

A proposed solution is to add a compatibility status alongside the overall agent health and fleet connection state:

sudo elastic-agent status --output=yaml
state: Healthy
message: Running
compatible: true/false
compatible_message: input IDs [A, B, C] are not compatible with <agentVersion>, remove them or upgrade to agent version <minCompatibleVersion>
fleet_state: Healthy
fleet_message: Running

where minCompatibleVersion is provided by the agent policy.

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[cmacknz]

Thanks! Note to the implementer: we have flexibility to change the formatting since this will only apply in the elastic-agent status output and in diagnostics in state.yaml. It's not part of the contract with Fleet.