ATLAS-5054: Introduce JaCoCo plugin and generate Code Coverage results with CI

[kumaab]

What changes were proposed in this pull request?

Integrate code coverage with JaCoCo in CI

• Introduce Maven JaCoCo plugin
• Merge all jacoco.exec files generated as part of JDK8 build into a single .exec file.
• Run report generation and upload artifacts for consumption

How was this patch tested?

Tested the changes in local docker build