Added github actions for basic build/test setup.

[mbien]

• builds/tests on JDK 11 and 17
• uploads junit report
• disabled a failing test for now

[mbien]

i think the junit report will start working once the yaml is in master.
should look like this: https://github.com/mbien/roller/runs/4631232068?check_suite_focus=true
and if something fails:
https://github.com/mbien/roller/runs/4631155838?check_suite_focus=true

[mbien]

added step for selenium tests (didn't know that geckodriver could run headless).

[snoopdave]

This looks very cool. I have not tried it out yet, but I see no reason not to merge.

[mbien]

awesome. I merge it, lets see if everything builds.

[mbien]

it builds and tests but it didn't upload the test report (it should appear on the list on the left i think)
https://github.com/apache/roller/actions/runs/1627718913

Don't know why because I tested it on my wip branch and it worked fine. (but its not so important tbh, the full log is recorded anyway in case something fails)

[mbien]

oh haha. It published it in he CodeQL action
https://github.com/apache/roller/actions/runs/1627718912

[mbien]

mikepenz/action-junit-report#40