feat(district,maps_utils): load map layer tiles from MapProxy instance

...ns/0075_remove_districthomepage_mapbox_apikey_and_more.py

district/models.py

...plates/district/district_geo_feature_collection_page.html

.../templates/district/district_geo_feature_detail_page.html

majak/settings/base.py

maps_utils/blocks.py

maps_utils/const.py

maps_utils/static/maps_utils/geo-feature-collection.js

...s/templates/maps_utils/blocks/map_feature_collection.html

maps_utils/templates/maps_utils/blocks/map_point.html

uniweb/migrations/0029_alter_uniwebarticlepage_content.py