Direct Luxembourg geozone synchronization and ED-269 import

Added direct synchronization of the official Luxembourg UAS geozone dataset.
Added upload support for .json and .geojson files up to 5 MB.
Added conversion of the official EUROCAE ED-269 zone structure to SkyMission GeoJSON features.
Handles UTF-8 BOM markers found in downloaded Luxembourg JSON files.
Converts Luxembourg authorization, prohibited, and conditional restrictions to SkyMission restriction levels.
Preserves altitude limits, validity periods, messages, reasons, and authority details from the source dataset.

Changelog