GUI: dae controls

As a user I would like to be able to control my DAE.

This is following on from #25 which made a good start at implementing an an OPI+perspective in the GUI for the diagnostic processes

Current PVs are here: https://isiscomputinggroup.github.io/kafka_dae_control/pvs.html

and obviously this should look somewhat similar to the current DAE view where it makes sense. I don't mind if placeholders are used for functionality that doesn't yet exist (periods, vetoes etc.)