CCON problems

[shrinktofit]

• [x] CCON can not be merged like existing JSON merge mech.

• [ ] CCON splits a resource into two parts on some platforms.

• [x] CCON requires a not well-known extension .cconb or .ccon and it's forbidden on many platforms.

[shrinktofit]

The extension name problem is relatively easy to solve. The proposed solution is:

• Refactor BufferAsset so that it can be serialized as CCON format. After this change, .bin extension will no longer be occupied by BufferAsset. PR: #15513

• Output CCON files with extension ".bin". Whenever asset system downloading a file with .bin extension, that file is recognized and parsed as CCON files:

  • Engine: https://github.com/cocos/cocos-engine/pull/15993
  • Editor: https://github.com/cocos/cocos-editor/pull/2425
  • Engine Extension: https://github.com/cocos/engine-extensions/pull/337
  • Platform Extension: https://github.com/cocos/creator-runtime-extensions/pull/467