Pass more context from Sidekiq jobs to Logster

Using the new recommended Sidekiq -> Logster reporter from [here](https://github.com/riking/logster/blob/clear/lib/examples/sidekiq_logster_reporter.rb)
@SamSaffron said:

> confusing, ... the idea for handle_exception is to allow you to just easily handle an exception, going through sidekiq was a convenience thing, the API is meant for general consumption.

Well, that's not how it's used currently. It uses a Sidekiq-specific logger, and all of the calls are from within Sidekiq jobs or the scheduler.