Prepare switch to Central Portal

[gsmet]

The plan is to use Njord - https://github.com/maveniverse/njord - which relies on the standard deploy plugin and then build a bundle to upload it to Central Portal.

Not really in a position to fully test this so we will have to merge and experiment for the next release.

We will have to backport this change to all the supported branches.

[quarkus-bot]

Thanks for your pull request!

Your pull request does not follow our editorial rules. Could you have a look?

• description should not be empty, describe your intent or provide links to the issues this PR is fixing (using Fixes #NNNNN) or changelogs

_{This message is automatically generated by a bot.}

[gastaldi]

I haven't used the njord plugin before, but the changes LGTM

[gsmet]

I haven't used the njord plugin before, but the changes LGTM

@cstamas has been extremely helpful and it looks a lot better conceptually so I really want to give it a try.