Implement basic modeller workflow enhancements enabled by the Python conversion

[jonmaddock]

The Python conversion affords many potential modeller workflow enhancements. Modeller workflow has previously been convoluted, repetitive and sometimes lacking straightforward reproducibility.

The scope of this epic is to capture, investigate, and implement some basic workflow improvements in consultation with the modellers. This has already involved the introduction of Jupyter notebooks for running Process and getting the tracking tool working (https://git.ccfe.ac.uk/process/process/-/milestones/30), but further enhancements can be thought of and implemented to improve the most common tasks when using Process.

• Discuss and capture modeller workflow enhancements #2899
• Input file validator #2900
• Create subset of tests for fast local running #2901
• Individual model running examples #3437