Remove vulnerable Maven versions, add support for 3.9.4

[Malax]

The list of supported Maven versions that are being installed only contained versions with security issues. Most notably CVE-2022-29599. This PR removes these versions as valid versions and adds the most recent 3.x version of Maven as the only supported (and therefore default) version.

• Update README with updated info about available Maven versions and the default.
• Remove integration tests for now unsupported versions.
• Use Apache's repository for downloading of the Maven distribution, this makes it easier to add new supported versions in the future.
  • These tarballs are different from the ones installed previously. We no longer need to normalize the contents, but now need to strip the first component since it contains the version number.

Closes GUS-W-13904493