Updated spatial validation to use UK Offshore Area

[KoalaGeo]

More geotechnical investigations are occurring offshore & therefore BGS will receive submissions of this data.

We currently use the UK coastline as one of the validation checks (https://github.com/BritishGeologicalSurvey/pyagsapi/blob/main/app/gb_outline.geojson).

This should be swapped for the UK offshore eea (https://github.com/BritishGeologicalSurvey/pyagsapi/blob/main/app/uk_eea_area_ex_ni.geojson)

We do need to maintain the Onshore NI checks (https://github.com/BritishGeologicalSurvey/pyagsapi/blob/main/app/ni_outline.geojson).

Logic:

If outside EEA & NI then EEA error/warning
ELSE same checks as currently

Deprecate Bounding Box Check - EEA performs same function

Tests:
Edinburgh = No error
Dogger Bank = GB Error so Offshore
Belfast with LOCA_GREF = No error
Belfast without LOCA_GREF = LOCA_GREF undefined
Kenya = Outside EEA error