LUCENE-9997: Collect signed maven artifacts if -Psign is passed.

[dweiss]

No description provided.

[janhoy]

I run the build with this patch, but get errors

> Task :lucene:backward-codecs:javadocJar
Caching disabled for task ':lucene:backward-codecs:javadocJar' because:
  Build cache is disabled
Task ':lucene:backward-codecs:javadocJar' is not up-to-date because:
  Output property 'archiveFile' file /Users/janhoy/git/lucene/lucene/backward-codecs/build/libs/lucene-backward-codecs-9.0.0-javadoc.jar has been removed.
:lucene:backward-codecs:javadocJar (Thread[Execution worker for ':' Thread 6,5,main]) completed. Took 0.072 secs.
:lucene:backward-codecs:signSignedJarsPublication (Thread[Execution worker for ':' Thread 6,5,main]) started.

> Task :lucene:backward-codecs:signSignedJarsPublication FAILED
Caching disabled for task ':lucene:backward-codecs:signSignedJarsPublication' because:
  Build cache is disabled
Task ':lucene:backward-codecs:signSignedJarsPublication' is not up-to-date because:
  Task has failed previously.
:lucene:backward-codecs:signSignedJarsPublication (Thread[Execution worker for ':' Thread 6,5,main]) completed. Took 0.002 secs.
[...]
FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':lucene:backward-codecs:signSignedJarsPublication'.
> Cannot perform signing task ':lucene:backward-codecs:signSignedJarsPublication' because it has no configured signatory

[janhoy]

I made the build pass when trying the java-based signing (-Psign -Psigning.keyId="xxxxxxxx" -Psigning.password=$GPGPASS -Psigning.secretKeyRingFile=$HOME/.gnupg/secring.gpg), but it does not work for gpg (-Psign -PuseGpg -Psigning.gnupg.keyName="xxxxxxxx" -Psigning.gnupg.passphrase=$GPGPASS)

[dweiss]

Eh. Ok, I'll take another look. It's all a bit of a black-box with those plugins...

[dweiss]

I've corrected the setup to configure the signing plugin across all projects - this should fix the problem. It works for me locally (with gpg), although on Windows it displays concurrent lock warnings (multiple threads trying to sign at the same time). I don't think it's a problem.

It also made me think whether we need two options... perhaps -Psign could be an alias for the java-based signer and -Psign=gpg could be used to indicate signing via GPG? One option less to remember? Can be done later as well.