Update UQCSBot Jenkins build to use Jenkins pipelines

[TRManderson]

UQCSBot has a fairly simple Jenkins setup right now, it's just "run a bunch of shell commands in sequence". Unfortunately, the way it's set up means tests passing with a linting failure won't correctly write coverage reports and so it goes kaput.

We can do a lot of far more nuanced things WRT how to handle error cases in Jenkins features (rather than in shell scripts we write) if we use Jenkins Pipelines, and this would also fully document how our Jenkins job is configured.