Define strategy for central config

[estolfo]

For the experimental version of the extension, the agent will disable central config but we need to figure out a strategy for the long-term.

[lucabelluccini]

We need to document this limitation in our docs. We filed:

• Added a note on centralized agent config support for AWS Lambda apm-agent-nodejs#3836
• Added a note on centralized agent config support for AWS Lambda apm-agent-java#3498
• Added a note on centralized agent config support for AWS Lambda apm-agent-python#1954
• [DOCS] APM AWS Lambda doesn't support APM Central config #432

We would hand over to the Docs team for refining/merging & backporting

FYI @someshwaranM

[kruskall]

Is there a reason why we can't just forward the agentcfg requests ?

[basepi]

Is there a reason why we can't just forward the agentcfg requests ?

Python handles central config in a separate thread. Disabling metrics collection and central config brings us from three background threads to one.

Also, since it's not typically a long-running process, it could spend a fair amount of time out of sync with central config on startup. Typical web apps are long-running, so the out-of-sync time is minimal.