diagnostic RPC

[xlc]

Some RPC to help diagnostic issues. Disabled by default. Optionally require an API key configured via config file so we can enable it on public server without exposing those RPC publicly

• A method to clear cache so we can check if an issue is caused by bad cache
• A method to force rotate endpoint so we can check if an issue is caused by bad upstream connection
• A method to drop current ws server and create one so we can drop all current connections and check if that help fixes whatever issue we have