Each registered agent in the fleet contains information about it's local meta

For synthetics, we ask user to use elastic-agent-complete variant which also contains browser dependencies. From synthetics plugin in kibana, we would like to determine if the agent registered is complete or not and hence warn user if they are trying to run browser monitor on simple elastic agent.

For that we need that information in the local_meta of the agent. So when user installs an agent and if its an elastic-agent-complete docker image https://hub.docker.com/r/elastic/elastic-agent-complete, we should add a flag saying. Its an es agent complete. So that we can consume that info in kibana.