Capture additional code coverage data

[planetf1]

• captures code coverage data for unit tests (only) [fvt can follow] for gradle build
• Since we only have a verification build in gradle, it is done there, ie for a PR - not a merge
• output is attached as a build artifact. It includes a CSV, as well as a tree of html files
• Report is only ordered by package name. There is no breakdown by artifact/directory (the plugin does not support this)

See #3969 for more info

[planetf1]

After reviewing results, some further work is needed. The report is not uploaded, as it is not run in the current './gradlew build' invocation. the task needs to be run explicitly (easy - run './gradlew codeCoverageReport - except that then the FVTs would run twice)
Need to review the network of task dependencies to determine the best to add to ensure the report is built at the correct time. The FVTs themselves probably need modifying so that they run when the assembly is rebuilt or tests modified, but not at other times
Moved to draft

[planetf1]

• Added support to maven poms for our FVT tests to try and capture code coverage data there-
• removed sonar exclusions from FVT tests (I think caused by original heavy types testing code)

[planetf1]

Merging, as this should improve sonar reports, but due to the pipeline setup we'll only verify once merged. Further changes to improve code coverage capture can follow in other PRs.