Add support for PMTiles-based layers

[claustres]

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

• Map background based on OpenStreetMap data with OpenMapTiles styles (linked to Mapbox style conversion function leaflet-pmtiles#1)
• GeoJson-like layers based on custom KDK style (linked to KDK style conversion function leaflet-pmtiles#2)
• GeoJson-like layers based on Leaflet path style (linked to Path style conversion function leaflet-pmtiles#3)
• GeoJson-like layers based on paint/label rules
• Manage interaction with the layer features (linked to Manage interaction leaflet-pmtiles#4)