update: implement lake_name in relation and measurement fetch

app/lib/server_requests/fetch_markers.dart

app/lib/server_requests/fetch_relation.dart

server/database/icedb

server/main.py

server/map_handler/__pycache__/add_lake.cpython-311.pyc

.../map_handler/__pycache__/get_measurements.cpython-311.pyc

server/map_handler/add_lake.py

server/map_handler/get_measurements.py

server/map_handler/lake_relations/all_lake_names.json