Cleanup ci containers

ci-containers/build.gradle.kts

.../src/main/kotlin/de/kuschku/ci_containers/CiContainers.kt

.../kotlin/de/kuschku/ci_containers/CiContainersExtension.kt

...lin/de/kuschku/ci_containers/GitlabCiProvidedContainer.kt

...main/kotlin/de/kuschku/ci_containers/ProvidedContainer.kt

.../kuschku/ci_containers/TestContainersProvidedContainer.kt

...main/kotlin/de/kuschku/ci_containers/providedContainer.kt

libquassel/build.gradle.kts

...sel/src/test/kotlin/de/kuschku/libquassel/EndToEndTest.kt

...kotlin/de/kuschku/libquassel/testutil/quasselContainer.kt

settings.gradle.kts