No easy way to get geojson submissions from FMTM/ODK

[spwoodcock]

Is your feature request related to a problem? Please describe.

@manjitapandey related to E2E feedback.

• There is no easy way to get submission data in GeoJSON format.

Describe the solution you'd like

Backend:

• Following on from Frontend buttons to load Entities in ODK Collect by intent #1449 we should get the submission data via OData endpoint, using osm-fieldwork OdkCentralAsync.OdkEntity.getEntityData().
• This data should be parsed and then passed through the same logic that currently sits in /helper/convert-odk-submission-json-to-geojson.
• The result should be GeoJSON format submission data from a submission router endpoint.

Frontend:

• There should be a new button added in the download section:
• 
• The button should say 'Submissions' and download the data in GeoJSON format from the new endpoint.

Additional context

• OData / Entities significantly improve this workflow, as in the past we had to cache the submissions in S3.