Python 3: Implement new import mechanism #5262
Description
As a developer, I would like to not do from * import * for every instrument script because that causes namespacing issues and isn't good practice. I would like to use the mechanism documented at https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/instrument-scripts#future-new-mechanism which seems more sensible.
Acceptance criteria:
- Configs are updated to use the new mechanism
- ConfigChecker scripting directory tests are updated to reflect this new mechanism
- Instrument scripts are updated to work
- Appropriate documentation for scientists created