Scripting console: API (?) to automate clearing the console

The output of the scripting console in the GUI has a limited size to avoid it taking large amounts of memory. As a muon scientist I would like to automatically clear the console at certain times, so that I don't run into this limit mid-experiment.

The suggested implementation of this ticket is to have an API in genie_python that talks to the GUI and tells it to clear the console. This is done elsewhere using py4j. The scientists would then hook into this API to clear the console automatically when, for example, a new RB number is set.

# Acceptance criteria:
- Console can be cleared in an automated way