Release cavity simulator module

Module from in-kind partner repository (https://gitlab.esss.lu.se/kacperklys/e3-cavitysimulator).

There was that e3-review branch that was not merged. I started from there and did some cleanup.

TODO:

• update EPICS environment to 7.0.8.1
• remove files from e3-cavitysimulator/cavitysimulator, leave only cavitysimulatorApp (was moved to https://gitlab.esss.lu.se/epics-modules/cavitysimulator)
• move OPI (moved to https://gitlab.esss.lu.se/opis/dev-rf/gui-cavitysimulator)
• run pre-commit