build(ci): Basic Gradle workflow to build on Github

[skaldarnar]

Contains

A Github workflow to build, test, and analyze the code.

Uses Gradle Build Scans for reporting, see https://docs.gradle.com/enterprise/gradle-plugin/#connecting_to_scans_gradle_com (automatically accepted for CI runs, but no for local runs).

How to test

• ensure that gradlew distForLauncher --scan still prompts for user agreement
• ensure that the jobs look reasonable and work correctly (for instance, ❌ when build should be failing)
  Currently the integration-test step is failing with varying test cases, while they are working on Jenkins…

Additional Tasks

• configure mandatory checks to use Github jobs instead of Jenkins jobs for now

[jdrueckert]

further extracting jobs (if desired) can be done as a follow-up

[jdrueckert]

would it make sense to extract those into dedicated jobs, too?

[skaldarnar]

hm, if we get the job dependencies with reuse going then yes, otherwise I would not blow up the job count as this job with multiple steps is still faster than the other two…

[jdrueckert]

would it make sense to split into mandatory (checkstyle) and not mandatory (spotbugs, pmd) ones here?

[skaldarnar]

We could - depends a bit on what we want to see in Github and/or how we view the build results.

Currently, we're more interested in the binary ❌ / ✔️ than anything else

[skaldarnar]

At least locally, the integration tests were successful with cf0d2ae

[skaldarnar]

Hm, I have no clue about the failing tests 😔

In https://github.com/MovingBlocks/Terasology/actions/runs/6066596499/job/16457362691?pr=5134

 ExampleTest > testSendEvent() FAILED
    java.lang.RuntimeException at ExampleTest.java:65

170 tests completed, 1 failed, 10 skipped

In https://github.com/MovingBlocks/Terasology/actions/runs/6066441235/job/16457033053

 DelayManagerTest > delayedActionIsTriggeredTest(ModuleTestingHelper) FAILED
    java.lang.RuntimeException at DelayManagerTest.java:40

ExampleTest > testClientConnection() FAILED
    java.lang.RuntimeException at ExampleTest.java:42

170 tests completed, 2 failed, 10 skipped

In https://github.com/MovingBlocks/Terasology/actions/runs/6066440639/job/16457031736

 ExampleTest > testClientConnection() FAILED
    java.lang.RuntimeException at ExampleTest.java:42

ExampleTest > testSendEvent() FAILED
    java.lang.RuntimeException at ExampleTest.java:65

170 tests completed, 2 failed, 10 skipped

[jdrueckert]

testSendEvent has been failing every now and then for a while now if you look at the past commits...

[skaldarnar]

Jenkins is working at the moment, so I don't think we have a need to get this merged. Two different pipelines at the same time don't make much sense, thus, closing this PR.