Optimize Spine renderer and refactor Spine loader

Description:

This PR creates a separate branch to manage the Spine 4.2 runtime version.
Updated the runtime to address some issues archived in Milestone 1.3: #88 #85 #66 #93 #94
Merged SpineRenderer and SpineAnimation, and made SpineAnimation inherit from Renderer to streamline the API.

Detail change:

example/main.ts : Update examples for new runtime api
example/outline.ts: Fix some type script type error
index.html: add upload dom element for local file upload example
package.json: change package name
rollup.config.js: Remove mini program support ( old mini program pack logic cause build error
src/SpineAnimation.ts: Refract : Inherit from engine renderer，streamline spine api
src/SpineRenderer.ts: remove
src/core/MeshGenerator.ts: Support multi texture & Updated to adapt to the modifications in the renderer.
src/core/SpineMesh.ts：Updated to adapt to the modifications in the renderer.
src/index.ts：Update package exports
src/loader/LoaderUtils.ts： Refract Loader , Consolidated core loading functions into loaderUtil.
src/loader/SpineLoader.ts： Refract Loader to address issues
src/spine-core/index.ts：Export all spine-core classes
src/spine-core/polyfills.ts: Export module.

spine-core update：Updated spine-core, use npm module instead.

galacean / engine-spine