gstlal_ll_inspiral_event_plotter: add a separate job to the DAG for plotting injection events

We've observed an issue with the event plotter job where not every event uploaded to GraceDB has plots associated with it, especially if there are multiple events at the same time.

The way the job works is that it receives Kafka messages for each GraceDB event and loops over those received messages producing plots to upload to the event. However, making all the plots can take several minutes and since messages only stay in Kafka for 100 seconds, I believe sometimes the program is missing messages, ie it's unable to consume new messages while it's in the process of handling previous messages.

The first pass solution to this is to make a duplicate plotter job in the DAG so that we have one to process non-injection events and one to process injection events. This will also be more consistent with how we've separated injection and non-injection processing in the rest of the workflow. This MR adds the separate job and makes associated changes to upstream programs (gstlal_inspiral, gstlal_ll_inspiral_event_uploader) to send data to separate inj and non-inj topics.