Issue is WIP

Specification

1. agentService is a public service, so it should not have authorisation, but in the current implementation, it does. Which is to be altered.
2. agentService currently does not use timeoutMiddleware, which it should.

Additional context

js-rpc has a sister PR which addresses the same issues - MatrixAI/js-rpc#42

Tasks

1. Remove authorisation from AgentRPCRequestParams and AgentRPCResponseResult
2. Implement timeoutMiddleware for agentService