AV-57335 POC for analytics include using collector

[osfameron]

To simplify process for Analytics team, we can use https://gitlab.com/antora/antora-collector-extension/

NOTE: this extension is currently Alpha, will have to discuss with OpenDevise.

This PR will add the Couchbase fork of AsterixDB and the Collector extension.
A subsequent PR on the AsterixDB repo will provide a command to aggregate sources.
couchbase/asterixdb#2

The .adoc file in this PR includes one of these files, using the Markdown block (modified to cope with the use of HTML in AsterixDB sources)

[osfameron]

@mojavelinux I've wanted to test this extension out for a while since @RayOffiah mentioned it, but was blocked on the Antora 3.1 upgrade.
This POC was much easier than expected, this is a really powerful feature for exactly this kind of issue (3rd party repos where we have minimal control over the content structure.)

I've raised one minor issue on GitLab -- which may just be a bad expectation on my part.

The extension is currently marked Alpha. Do you recommend that we proceed beyond this initial demo to a fully fleshed out POC?

[mojavelinux]

The extension is currently marked Alpha. Do you recommend that we proceed beyond this initial demo to a fully fleshed out POC?

I would be cautious. Alpha means that the extension could change at any time and that we might even completely redesign it. There are no guarantees. However, if you're prepared for a potential migration in the future, then you can use the version that is released and either stay with that or do any necessary migration when 1.0.0 is available.

[osfameron]

OK. Assuming that we're using the package as intended, then it feels like even a substantial redesign should be manageable with a reasonable effort (update configuration, update paths, change how the command payload is called etc.)

I'm ok with that from tooling side, @simon-dew what do you think as stakeholder?