post utiles-core next steps

- [x] `UtilesError` should become `UtilesCoreError` and main `utiles` lib should get `UtilesError` - [x] Super basic mbtiles server (yay! another rust learning experience) - [x] Expand on current sqlite extensions so we can do more stuff just w squeal queries - [x] Settle on some sort of pool/lib for async mbtiles stuff (i do not vibe with sqlx) - `uitiles`: super secret deckgl + maplibre mbtiles inspecter thing I have been working on - [ ] move into this repo - [x] figure out way to embend the jawascript bundle into super simple server mentioned above