[gu] Opening up the catalog to the community

[fniephaus]

It'd be great if the GraalVM CE Updater catalog could be opened up to the community, so that third-party languages, tools, etc. can be added.
This also requires some sort of documentation for how to contribute to the catalog.

Somewhat related, what are these two undocumented catalog files for?
/~https://github.com/graalvm/graalvm-ce-dev-builds/blob/55f41bd3c9606ca8296651c110d7637ac0486090/catalog.jdk_8.properties
/~https://github.com/graalvm/graalvm-ce-dev-builds/blob/55f41bd3c9606ca8296651c110d7637ac0486090/catalog.jdk_11.properties

[fniephaus]

Are there any updates on this?

[performantdata]

The property names appear to be defined in BundleConstants. RemotePropertiesStorage.loadComponentMetadata appears to be central to the loading.

[fniephaus]

GraalVM updater has been removed #6855 so this is no longer relevant.