Customization of code reports

This is codecov: https://about.codecov.io/
What we have can be seen here, it's an alternative: https://github.com/boostorg/url/pull/861 . Find on the page GCOVR.
That is already working. It could be enhanced so the gcovr report is more customized in appearance. But otherwise, the mechanism is already in place.

What the web developers might get involved in, is customizing the layout, the colors, the arrangement, the css stylesheets.

There's a server instance running Jenkins. The code it uses has been migrated into this repository: https://github.com/cppalliance/jenkins-ci

Any time a codecov-type job should be set up, I would add that to the server. Some scripts also reside in https://github.com/cppalliance/ci-automation/tree/master/scripts

What needs to be done...
when the job runs, it's generating a plain "lcov" report. And a plain "gcovr" report. So, two pages.
It could be enhanced so the gcovr report is more customized in appearance.

This is what enabled customization. https://github.com/gcovr/gcovr/pull/758

**Dev process:**
Here is a script which is called: https://github.com/cppalliance/ci-automation/blob/master/scripts/lcov-jenkins.sh
It's slightly tricky to get a development environment set up that's running that.
But once it's set up, you can work on the stylesheets and so on, of the output files.

Fork a repo such as boostorg/url. Sam can add that to Jenkins. Then, push trivial updates as often as needed.