showcase: convert "From Blender to BabylonJS" scene to _r

[Vinc3r]

I have to convert this demo using _r https://www.nothing-is-3d.com/data/medias/folio/3drealtime/lightmaps-workflow-tutorial/demo.html for showcase page.

• make a precision about the use of custom engine, as CStfan asked
  example, to force webGL1: var engine = new BABYLON.Engine(canvas, true, {disableWebGL2Support: true, useHighPrecisionFloats: false});
• when _r fixed, rephrase lightmaps assignation part where material : { subMaterials : { "*" are used
• see also getting mesh name: Get objects above in hierarchy inside patch _r#23
• inspector on final scene freeze

[Vinc3r]

• make a precision about the use of custom engine, as CStfan asked
  example, to force webGL1: var engine = new BABYLON.Engine(canvas, true, {disableWebGL2Support: true, useHighPrecisionFloats: false});
• utiliser des codesandbox

[Vinc3r]

pense-bête pour l'assignation lightmaps:

"wallz.000" : {
    material : {
        lightmapTexture : _r.load("assets/lightmaps/wallz.000_LM.png
    }
},
 "furnitures.000" : {
    material : {
        lightmapTexture : _r.load("assets/lightmaps/furnitures.000_LM.png
    }
 }