Introduce automatic linting with Github workflows (#251)

* Add linters

* use other setup-python version

* Use string instead

* Add more linting

* Fix tests

* minor changes

---------

Co-authored-by: Marcus Valtonen Örnhag <marcus.valtonen.ornhag@ericsson.com>

.github/workflows/tests-frontend.yml

@@ -0,0 +1,17 @@
+name: tests
+
+on: [push, pull_request]
+
+jobs:
+  prettier:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18
+      - name: Run prettier
+        run: |
+          cd frontend
+          npm install
+          npx prettier --check .