Move to vector maps (MapLibre)

[goteusz-maszyk]

As "part" of #44, we definitely should switch to vector maps. They make maps more interactive, require less resources to run and give more customization options.

This would involve switching rendering system to Maplibre GL, which supports raster tiles that may come from other sources as other layers.

Vector tiles will also let us remove annoying "what's here"/"query features" thing.

Requirements:

• [ ] Set up a tile server, most preferably OpenMapTiles or find one that lets us use their resources for free
• [ ] Rewrite the entire map rendering system
• [ ] Let users upload their own custom styles
• [ ] Make objects clickable