Add model output file schema repair functionality

[annakrystalli]

! Unsure whether this should live here or in hubAdmin

Background

For a hub to be successfully accessed as an arrow dataset, column data types should not change from round to round.
Generally many task IDs that are covered by our schema shouldn't change data type in further rounds as that's somewhat fixed by the schema. Custom task IDs however, which are beyond our control, and the output_type_id column have the potential to change and this could indeed cause problems downstream. This is mainly a problem for parquet files (but has a small chance to cause problems in csvs too).

To reduce the chances of this happening/mitigate the effects, a number of actions have been proposed:

• Improve the documentation on this, get admins to think about the issue early on and warn them to avoid changes in data types.
• Should propagate the ability to fix the output_type_id column to hubValidations ( Introduce output_type_id_datatype argument across relevant validate_*() fns #91) and consider a property in the schema where hub admins can configure and communicate this setting (Introduce a property to fix the output_type_id column data type across the hub schemas#87).

Add model output file schema repair functionality

As a future feature, once we have created functionality to inspect a hub for integrity and the following have all been implemented:

• Function and action that scans and reports on the “health/integrity” of a repo periodically #83
• Introduce a property to fix the output_type_id column data type across the hub schemas#87
• Add from_config option to output_type_id_datatype and set as default setting hubData#44
• Introduce output_type_id_datatype argument across relevant validate_*() fns #91

we could also add functionality that could repair any data type discrepancies and update files to conform to a changed schema. This could help admins in a situation where all the above fail and a breaking schema change needs to be introduced.