gitlab-ci: Add minimal build configuration

Ensures KWin is also built with features disabled to catch when code is
added that requires a build-time guard

Signed-off-by: Eike Hein <eike.hein@mbition.io>

.gitlab-ci.yml

@@ -4,3 +4,7 @@
 include:
   - https://invent.kde.org/sysadmin/ci-utilities/raw/master/gitlab-templates/linux.yml
   - https://invent.kde.org/sysadmin/ci-utilities/raw/master/gitlab-templates/freebsd.yml
+
+suse_tumbleweed_qt515_reduced_featureset:
+    extends: suse_tumbleweed_qt515
+    script: python3 -u ci-utilities/run-ci-build.py --project $CI_PROJECT_NAME --branch $CI_COMMIT_REF_NAME --platform Linux --extra-cmake-args="-DKWIN_BUILD_DECORATIONS=OFF -DKWIN_BUILD_KCMS=OFF -DKWIN_BUILD_SCREENLOCKER=OFF -DKWIN_BUILD_TABBOX=OFF -DKWIN_BUILD_ACTIVITIES=OFF -DKWIN_BUILD_RUNNERS=OFF -DKWIN_BUILD_NOTIFICATIONS=OFF" --skip-publishing