Add support for PMTiles-based layers

[claustres]

We should rely on https://github.com/kalisio/leaflet-pmtiles, typical use cases are:

• [x] Map background based on OpenStreetMap data with OpenMapTiles styles (linked to https://github.com/kalisio/leaflet-pmtiles/issues/1)
• [ ] GeoJson-like layers based on custom KDK style (linked to https://github.com/kalisio/leaflet-pmtiles/issues/2)
• [ ] GeoJson-like layers based on Leaflet path style (linked to https://github.com/kalisio/leaflet-pmtiles/issues/3)
• [x] GeoJson-like layers based on paint/label rules
• [ ] Manage interaction with the layer features (linked to https://github.com/kalisio/leaflet-pmtiles/issues/4)