Feat: refactor spine loader & add ability for dynamic skin change

[johanzhu]

What does this PR do?
Adjust spine basic API.

Related issue:
#110

Changes

• src/SpineAnimationRenderer.ts ： Fix bounding box bug.
• src/index.ts: Export util function for dynamic skin change.
• src/loader/EditorSpineAtlasLoader.ts: Adapt to 1.3.20 resource manager api.
• src/loader/LoaderUtils.ts: Add createSpineResource and createTextureAtlas function.
• src/loader/SpineLoader.ts: Refactor loader, optimize code.
• src/loader/SpineResource.ts: Change url param to name.
• src/util/AttachmentTools.ts: Add util for create attachment based on new region.
• src/util/BufferReader.ts: Delete reader, use engine reader.
• vite.config.js: change listen port.

Dynamic change examples:

1. Change atlas by creating a new spine resource

const textureAtlas = await engine.resourceManager.load({
    url: '/spineboy-pro.atlas', // your new atlas
  });
  const spinejson = await request(
    'https://mdn.alipayobjects.com/oasis_be/afts/file/A*7e6nSLQT9gsAAAAAAAAAAAAADkp5AQ/spineboy.json',
    {
      type: 'text',
    }
  );
const spineResource = createSpineResource(engine, spinejson, textureAtlas);
const entity = spineResource.instantiate();
root.addChild(entity);

2. Change attachment using a new atlas.

const renderer = entity.getComponent(SpineAnimationRenderer);
 const { skeleton, state } = renderer;
const slot = skeleton.findSlot(slotName);
const region = atlas.findRegion(regionName);
const originalAttachment = slot.attachment as RegionAttachment | MeshAttachment;
if (region == null) {
  slot.attachment = null;
} else if (originalAttachment != null) {
  slot.attachment = cloneAttachmentWithRegion(originalAttachment, region);
} else {
  slot.attachment = createAttachmentFromRegion(region, region.name);
}

[singlecoder]

If there is an exception, return null to let the caller be aware.

[johanzhu]

done

[singlecoder]

If there is an exception, return null to let the caller be aware.

[johanzhu]

Using JSON.parse to determine whether atlasText is editor asset is the most straightforward approach.
If parsing fails, it indicates that the text is not JSON and is instead a none editor Spine atlas asset.
If the raw asset is invalid, an error will be thrown when creating a new TextureAtlas.

[singlecoder]

check is editor asset should be simpler?