LFRic Apps apply upgrade macros script (Part 1)

[james-bruten-mo]

This PR is to add the main part of the upgrade macro script for applying macros to LFRic. As described in #37 this work will be done in 2 commits, of which this is the first. This code will read through versions.py files, searching for newly added macros, and combine these macros where necessary. The 2nd part will add the rose commands to apply the upgrade macros as well as adding unit tests. Some development history and testing examples can also be seen in lfric_apps:#139 including a description of the overall approach on the details page. A PR for the working practices also exists.

This PR adds:

• a main and parse args section
• introduces the ApplyMacros class which is where the majority of the code is. This contains:
  • a section for sourcing required lfric_core and jules working copies (as these contain required metadata)
  • a section for reading and combining new upgrade macros (the majority)
• some initial functions outside of the above class which provide some general functionality

The script can be tested by getting the following 2 branches:

• fcm:lfric_apps.x_br/pkg/jamesbruten/vn1.1_macro_pkg
• fcm:lfric.x_br/dev/jamesbruten/core1.1_core_macro_branch

And then running apply_macros.py -a vn1.1_t139 /path/to/apps -c /path/to/core. This upgrade macro is present in lfric_atm, transport, gungho and components/driver. After running the script, it should be removed from gungho and driver, combined with the existing macro in atm and transport and added to any metadata that imports any of those 4 (most of them in fact!).