Add support for TileJSON

[maxammann]

maplibre-rs currently only supports downloading tiles directly. We hardcode the TMS/XYZ format in the code.

🤔 Expected Behavior

maplibre-rs can use a tilejson hosted at: https://example.net/tiles.json

😯 Current Behavior

maplibre-rs can only fetch files from https://example.net/x/y/z.pbf

💁 Possible Solution

Support the TileJSON spec. Supporting only part if it is sufficient.

🔦 Context

💻 Examples

None