migrate school, bar, bmw to catalog.json

[kfarr]

• Also, remove other elements from that category
• create thumbnails
• update positioning to v3 for buildings

        <a-mixin shadow id="building-school" gltf-model="url(${assetUrl}sets/school-building/gltf-exports/draco/school-building.glb)"></a-mixin>
        <a-mixin shadow id="building-bar" gltf-model="url(${assetUrl}sets/irish-bar-building/gltf-exports/draco/irish-bar-building.glb)"></a-mixin>
        <a-mixin shadow id="vehicle-bmw-m2" gltf-model="url(${assetUrl}sets/vehicles-rig/gltf-exports/draco/BWM_m2-rig.glb)"></a-mixin>