configure ATR project

[hboutemy]

https://release-test.apache.org/projects/maven

notice the download_path_suffix that is quite special to match our maven-X structure in https://downloads.apache.org/maven/ / https://archive.apache.org/dist/maven/ / https://dist.apache.org/repos/dist/release/maven/ / https://dist.apache.org/repos/dist/atr/maven/ / https://dist.apache.org/repos/dist/dev/maven/

{{MAJOR}} won't be automatically replaced by ATR at the Finish stage, but I hope the release manager will see and update (and we could probably ask Tooling to force reject such a value if it remains as-is when submitting the form)

@cstamas @gnodet do you intend to use ATR for managing the VOTE of next Maven releases?

notice:

• this PR can be back-ported to 4.0.x and 3.10.x branches, even if it won't really do anything there: just for consistency
• configuration of push-to-atr profile will be done in another PR

[hboutemy]

FYI, first draft of push-to-atr profile #12441

[hboutemy]

will require apache/tooling-trusted-releases#1381
for now, {{MAJOR}} is rejected, I updated by hand to MAJOR and release manager will have to replace after vote with effective value