Feat/clipping no fly zones

[Pradip-p]

Description

This PR introduces enhancements to our geometry handling to support multiple Polygon and MultiPolygon types in the no_fly_zones field and also render the task split with no-fly zones.

Changes

• Read and parse no-fly zones GeoJSON if provided.
• Calculate the difference between the project shape and no-fly zones.
• Generate the resulting GeoJSON feature with the new outline.

Geometry Merging:

• Implemented logic to merge multiple geometries into a single MultiPolygon using Shapely's unary_union.
• Ensured that if the merged geometry is not already a MultiPolygon, it is converted to one.

screenshot

[spwoodcock]

Via shapely is ok for now, but with PostGIS directly in the db would be a bit nicer 👍

Note I recently tried to standardise our GeoJSON usage for FMTM, taking into account multipolygons, z-index, etc: https://github.com/hotosm/fmtm/blob/f1ec17040f1ab8819cc62129c19dae7e51ef72d2/src/backend/app/db/postgis_utils.py#L409

I'm thinking of pulling these utils out into a separate package geojson-parsers that could be used in FMTM & Drone-TM, so we could refactor in the future 😄