[Schema] Minor and structural updates

[odscrachel]

There are a number of updates that need to be made to the schema to make it valid and to capture the minor changes in the spreadsheet. These minor changes will be captured in the changelog.

Changes include, but are not limited to:

• Changing definitions to $defs to match current JSON schema version
• Add missing definitions to fix errors
• Update field names and descriptions where indicated in the spreadsheet
• Update codelists
• Update which fields are 'required'
• Check integers are replaced with supported number type
• Remove defs that are no longer referenced
• Capital formatting in defs

[duncandewhurst]

• Add missing definitions to fix errors

#109 adds empty definitions in order to make the schema valid.

[duncandewhurst]

• Update field names and descriptions where indicated in the spreadsheet

#109 adds a test to make sure that definitions and properties have titles and descriptions. Presently, many titles and descriptions are missing so the test is commented out. We should enable the test when we go through add titles and descriptions from the spreadsheet to make sure that we don't miss any.

[odscjen]

Also include

• removal of fields as agreed in this spreadsheet

[odscjen]

I've updated the fields and descriptions spreadsheet to note which issues relate to which fields in the original schema. This should hopefully help us ensure we're covering everything that should be covered by this minor changes update

[duncandewhurst]

• Update field names and descriptions where indicated in the spreadsheet

#109 adds a test to make sure that definitions and properties have titles and descriptions. Presently, many titles and descriptions are missing so the test is commented out. We should enable the test when we go through add titles and descriptions from the spreadsheet to make sure that we don't miss any.

I've created a (draft) PR to enable the test: #128