Smarter bot calls

Description

Rather than having polling every N seconds, have the server wait on the job queue if there is no work available before a specified timeout, replying immediately if a job becomes available. Also set up bots to periodically try and reconnect if the server times out or stops replying.

Changes proposed in this merge request:

• Change underlying queue structure to Queue. This allows servers to wait on the job queue if none are available.
• Have bots specify a timeout in the grpc call, and have the servers check this.
• Get bots to reconnect.
• Add extra test. Asyncio does not seem to play well with something with the new tests setup, might just be better to leave this for behavioural tests.

This merge request, when approved, will close issue/bug:

Fixes #118 (closed) and #126 (closed)