49 process gadm administrative map and chirps rainfall data

[rowannicholls]

Written and tested functions:

DART-Pipeline
 └ B Process Data
    ├ process_data.py
    │  └ ✅ process_geospatial_meteorological_data()
    │     └ ✅ process_gadm_chirps_data()
    └ test_process_data.py
       ├ ✅ test_process_geospatial_meteorological_data()
       └ ✅ test_process_gadm_chirps_data()

[rowannicholls]

@jsbrittain it seems I created the pull requests in the wrong order - that's on me, my bad. The order should be #58, then #49, then #47

[rowannicholls]

@jsbrittain changes have been made

[jsbrittain]

@rowannicholls Thanks - that's much cleaner. Note that tests are failing (due to datetime.datetime). Once they're fixed we should be able to merge. 👍