Add wmts/xyz offline support to babylonjs

[dalidaliW]

Description

Add wmts/xyz offline support to babylonjs，Currently, Threejs is supported, while Babylonjs lacks support

Solution

Similar to the following implementation
let imgLayer = new Cesium.UrlTemplateImageryProvider({
url: “http:localhost:8888/{z}/{x}/{y}.png”,
minimumLevel: 13,
maximumLevel: 18,
});

Alternatives

Similar to the following implementation
let imgLayer = new Cesium.UrlTemplateImageryProvider({
url: “http:localhost:8888/{z}/{x}/{y}.png”,
minimumLevel: 13,
maximumLevel: 18,
});

Additional context

No response

[gkjohnson]

cc @georginahalpern