Internal enhancements and improvements: Improve default datasets

[amyburness]

Improve default datasets by making CHIRPS data available to users for national reporting drought hazard (SO3-1), allowing users to import national population data for use in SO2-3/SO3-2 indicators.

[amyburness]

Notes from UR meetings:

• [ ] @gabrieldaldegan hve the standardised precipitation index CHIRPS Data set as an alternative that must be incorporated as a default data set.
• [ ] We must allow users to use custom data sets stored locally (Nationalion data)
• [ ] These national data sets have to be processed locally and not in the cloud for the security of the data.
• [ ] We validate the custom data sets -> validation (document data standard with a validation message if incorrect)
• [ ] We may need to standardise the file type for custom data and document that.
• [ ] The national data for population will likely be census data and may come in different formats we will need to think about how it incorporates this. the data may not even be geospatial data.
• [ ] Currently, the default offered is graded world pop data.
• [ ] @alexbruy has the CHIRPS data and that has gone through some analysis to make it analysis ready.