Add/document plain-Jenkins integration

[gavanderhoorn]

Lifting this to a stand-alone issue here (from ros-infrastructure/ros_buildfarm#596 (comment)):

@max-krichenbauer wrote:

I understand that nlimpert/ros_buildfarm@7bc2d75 is no longer the approach you're going for, since whether or not HAROS can and should be used depends on the package.
I used it for my studies and experiments because I'm not developing any packages, so I wanted to "force it" onto the existing ROS packages.
The new approach of course makes much more sense.

However, I think it could be useful to offer both displaying the HAROS result in the wiki as well as in Jenkins. If there is interest I could prepare a cleaned-up PR.

I don't understand yet how the wiki works - the github page about it isn't extensively well documented. Any information on this topic would be very welcome.

[max-krichenbauer]

Thank you for offering this place to discuss and track the proposal.

For now I have started to work JUnit XML format output for HAROS, since it seems necessary to have it anyways for using HAROS in a linter package.

Then we can also use either the yaml output or the JUnit XML output to display test results in Jenkins / the build farm.
JUnit XML could be considered be more "clean" or "following common procedure".

[max-krichenbauer]

Here is the PR for a first implementation of JUnit XML format output:
git-afsantos/haros#79