Added Develocity setup

Following up on your interest in being part of the Eclipse Develocity evaluation initiative, this Merge Request will enable you to publish Build Scans to develocity-staging.eclipse.org as requested in the helpdesk ticket #5626.

Description

This PR publishes a build scan for every CI build and for every local build from an authenticated Eclipse committer. The build will not fail if publishing fails. Local and remote caching was left disabled on this PR by design so that the build is not affected by this change.

The build scans of the Eclipse membership.eclipse.org webpage project are published to the Develocity instance at develocity-staging.eclipse.org, hosted by the Eclipse Foundation and run in partnership between the Eclipse and Gradle. This Develocity instance has all features and extensions enabled and is freely available for use by the Eclipse membership.eclipse.org webpage project and all other Eclipse projects.

On this Develocity instance, the Eclipse membership.eclipse.org webpage project will have access not only to all of the published build scans but also to other aggregate data features such as:

• Dashboards to view all historical build scans, along with performance trends over time. For example, look at the Quarkus instance trends dashboard with the ci filter applied.
• Build failure analytics for enhanced investigation and diagnosis of build failures. You can also explore the Quarkus instance for example of a different OSS projects Develocity instance.
• Test failure analytics to better understand trends and causes around slow, failing, and flaky tests. Going to the Quarkus instance again, this will probably give you a better representation of the type of data available. You can also order it by flakiness, which is a good starting point when deciding which tests need fixing the most.

This will also enable you to (optionally) use build time optimization features, such as (remote) build caching and Predictive Test Selection.

More information can be read in the Eclipse announcement.

Please let me know if there are any questions about the value of Develocity or the changes in this pull request and I’d be happy to address them.

Note: I'd advise you to change the Maven project name in the root pom.xml, which is currently set to react-commons, which is also the name of the project detected by Develocity. I'm happy to implement this change, but I'm not sure whether that's referenced anywhere - I couldn't find any references other than the <parent> tags of subproject pom.xml files.

Note: Since this MR is from an external fork, Jenkins will (probably) not pick up the changes in the Jenkinsfile, so I'd advise testing them in a branch of your own before merging, if possible. This is especially important since this is the first project using the https://foundation.eclipse.org/ CI instance.