Restructure pipelines and badges

- Seperate test pipeline into E2E, integration and unit test pipelines.
- Improve documenetation for pipelines (ci-cd.md).
- Introduce naming convention for worklow files and names.
- Center badges with multiple files on README file.

.github/workflows/checks.security.yaml

@@ -0,0 +1,24 @@
+name: security-checks
+
+on:
+  push:
+  pull_request:
+    paths: [ '/package.json', '/package-lock.json' ] # Allow PRs to be green if they do not introduce dependency change
+  schedule:
+    - cron: '0 0 * * 0' # at 00:00 on every Sunday
+
+jobs:
+  npm-audit:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v2
+      -
+        name: Setup node
+        uses: actions/setup-node@v1
+        with:
+          node-version: 15.x
+      -
+        name: NPM audit
+        run: exit "$(npm audit)" # Since node 15.x, it does not fail with error if we don't explicitly exit