tidy top_level

[james-bruten-mo]

This PR slightly tidies the top level of the SimSys_Scripts repo, moving all (almost) scripts into their own directories.
The only remaining ones are the old suite_report and fcm_bdiff scripts which are left in their original place for now. I suggest we give it a release cycle or so and then delete these.

[jennyhickson]

styling.py isn't part of lfric_styling - the comment at the top says its appying umdp3 styling to source code. It looks like a copy of https://github.com/MetOffice/um/blob/main/admin/code_styling/styling.py (which is called by apply_styling) but with the definitions at the top now coming from styling_keywords.py. Not even sure if styling.py has all its dependencies in here. Could it even get removed? Or is it used by the UMDP3 checker (thats when it was pulled in)

Generally feels like an area that could be condensed down so that lfric_styling.py isn't actually needed but just passes an input to a more general script. Also not sure how the UM's apply_styling stuff differs from the umdp3_fixer and if those could be combined too!

styling_keywords.py does get used by both styling and lfric_styling so it probably makes sense to keep them together if they're all staying, but maybe rethink the folder name?

[jennyhickson]

thanks