adding resource group.

When many pipelines run at the same time, could cause some collision, false results, or not passing tests.
Restructured CI to avoid this from happening.

.gitlab/test.yml

-
-stages:
-  - test
+workflow:
+  rules:
+    - if: $CI_PIPELINE_SOURCE == "parent_pipeline"
 
 .test-core: &test-core
   stage: test
@@ -45,9 +45,12 @@ run-test-job:
     - pip install -r "$CI_PROJECT_DIR/plugins/netbox-cert-plugin/tests/requirements.e2e.txt"
     - pip install -r "$CI_PROJECT_DIR/tests/requirements.e2e.txt"
   script:
-    - env HOST="${TEST_HOST}" PORT="${TEST_PORT}" API_KEY="$API_KEY" pytest -s --junit-xml=tests-report-netbox-rps-plugin.xml "$CI_PROJECT_DIR/plugins/netbox-rps-plugin/tests/"
-    - env HOST="${TEST_HOST}" PORT="${TEST_PORT}" API_KEY="$API_KEY" pytest -s --junit-xml=tests-report-netbox-cert-plugin.xml "$CI_PROJECT_DIR/plugins/netbox-cert-plugin/tests/"
-    - env HOST="${TEST_HOST}" PORT="${TEST_PORT}" API_KEY="$API_KEY" pytest -s --junit-xml=tests-report-netbox-dist-plugin.xml "$CI_PROJECT_DIR/tests/e2e/"
+    - env HOST="${TEST_HOST}" PORT="${TEST_PORT}" API_KEY="$API_KEY"
+      pytest -s --junit-xml=tests-report-netbox-rps-plugin.xml "$CI_PROJECT_DIR/plugins/netbox-rps-plugin/tests/"
+    - env HOST="${TEST_HOST}" PORT="${TEST_PORT}" API_KEY="$API_KEY"
+      pytest -s --junit-xml=tests-report-netbox-cert-plugin.xml "$CI_PROJECT_DIR/plugins/netbox-cert-plugin/tests/"
+    - env HOST="${TEST_HOST}" PORT="${TEST_PORT}" API_KEY="$API_KEY"
+      pytest -s --junit-xml=tests-report-netbox-dist-plugin.xml "$CI_PROJECT_DIR/tests/e2e/"
   after_script:
     - deactivate
     - rm -rf "$CI_PROJECT_DIR/plugins/venv"
@@ -93,4 +96,3 @@ down-test-env-job:
     - run-test-job
     - run-robot-test-job
   when: always
-