Add some utilities to support incrementals via Jenkins infra pipeline-library

[alextu]

This is a follow up of https://github.com/jenkinsci/gradle-jpi-plugin/issues/215 that is not sufficient to publish incrementals when running on ci.jenkins.io, since it would require passing credentials. Instead some plumbing is required in https://github.com/jenkins-infra/pipeline-library/blob/master/vars/buildPluginWithGradle.groovy like it's done on the Maven side:

• Running a build to generate the version file containing the sanitize version (a, b not allowed)
• Running the build overriding the version with -Pversion and archiving the resulting artifacts
• Call infra.maybePublishIncrementals() that should eventually caused an external service to pull the artifacts and publish them on Artifactory

This PR adds the necessary hooks to achieve this:

• one additional option is available to sanitize the version according to Jenkins requirement

• version format and version file path can be customized via Gradle properties

• [x] Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!

• [x] Ensure that the pull request title represents the desired changelog entry

• [x] Please describe what you did

• [x] Link to relevant issues in GitHub or Jira

• [x] Link to relevant pull requests, esp. upstream and downstream changes

• [x] Ensure you have provided tests - that demonstrates feature works or fixes the issue

[sghill]

Thanks @alextu! This is out at v0.49.0-rc.1

[alextu]

Thanks 👍, I really appreciate your reactivity !