Feat: v8 examples update

[bbazukun123]

Resolves ticket.

• Update example codes to work with PixiJS v8.
• Rename Simple Plane example to Mesh Plane.
• Added Fill Gradient example under the basic section.
• Remove examples:
  • Cache As Bitmap
  • Interleaving Geometry
  • Gradient Basic
  • Gradient Resource
• Examples to be verified with the latest next-v8:
  • Scratch Card: Brush graphic doesn't move causing the strokes to be of a slit.
  • Spinner: Artefacts with graphic mask on graphic.
• Examples to be updated after the availability of Shader.from(vertex, fragment, uniforms):
  • Mouse Blending Advance Filter
  • Custom Advance Filter
  • Shader Toy Filter Render Texture DELETED
  • Triangle
  • Triangle Color
  • Triangle Textured
  • Uniforms DELETED
  • Shared Geometry
  • Shared Shader
  • Instanced Geometry
  • Merging Geometry DELETED
  • Multi Pass Shader Generated Mesh
  • Shader Toy Mesh
• Known Issues:
  • Blur and Displacement filters: The outcome on the examples are slightly different to previous versions, ie. Blur has some slit artefacts during animation and the displacement doesn't seem to yield an expected zoom effect. UPDATE: The artefacts only happen on WebGPU!
  • Filter Mask: The blur filter doesn't seem to be captured with renderer's generateTexture
  • Simple Graphics: .star(..) doesn't seem to do anything.
  • What's the new approach to new Filter(vertex, fragment, uniforms)?
  • Nested Boundary With Projection example to be investigated. DELETED

Preview

Build: https://pixijs-v8-website-preview.surge.sh/next/examples