Add extension metadata to all the extensions

[gsmet]

Following the integration of https://github.com/jbossas/protean-shamrock/pull/663/files#diff-2cfc93ecb828363d0be95549c3abbbfeR31 , we need to add the appropriate metadata to all the existing extensions.

See our extensions.json for some label ideas.

[gsmet]

Check #832 as a follow-up of this one.

[dmlloyd]

We should be thinking of a way to unify this information with the descriptor that we must add for the Curate phase. There's no reason to have two different descriptors which do approximately the same thing.

[kenfinnigan]

If the curate phase uses the Extension class then it can become the metadata for an extension across everything

[dmlloyd]

The curate phase is happening during the bootstrap stub, so we probably can't/shouldn't bring in a JSON parser. What about using a properties format instead?

[gsmet]

So there are 2 different things:

• the actual metadata are properties in the pom file of the extension (see link above)
• then a JSON file is created for consumption by others (Web UI...)

[gsmet]

I think we can live with it for now. Removing the first-public-release tag: we can do that later, the current JSON file works well enough.

[maxandersen]

Since GA is now getting closer we should do this.

• add the labels, cateogories, etc. to the quarkus-extension.properties
• extension.json should then be generated from this file.