Consider merging 'glTF-Generator-Registry' into this repository?

The repository [KhronosGroup/glTF-Generator-Repository](https://github.com/KhronosGroup/glTF-Generator-Registry) hosts a [`registry.json`](https://github.com/KhronosGroup/glTF-Generator-Registry/blob/main/registry.json) file containing a list of tools that author glTF files. The list hasn't really been updated since 2018 and is likely out of date compared to this repository. One useful thing it does include, not present here, is a repository of [`asset.generator`](https://www.khronos.org/registry/glTF/specs/2.0/glTF-2.0.html#asset) strings allowing tools to take a given glTF asset, identify the tool that produced it, and find the documentation and bug report URLs (if available) for that tool. My viewer (https://gltf-viewer.donmccurdy.com/) uses this data to tell users where to report issues, when possible.

Since we probably don't want to be maintaining — or asking the community to maintain — two separate lists, perhaps it's worth adding `generator` strings and similar fields to the JSON records in this repository, and archiving the glTF-Generator-Registry repository?

Start by reviewing the external registry.json and the JSON records in this repository, then compare the generator information and available URLs. Determine the fields and migration scope needed to combine the registries, including the proposed archival of glTF-Generator-Registry; the issue is done when the maintainers agree on and implement that consolidation.

Written by the indexing model from the issue text.