docs: add logo for project, expand readme (#7)

Reviewed-on: #7
Co-authored-by: M.V. Hutz <git@maximhutz.me>
Co-committed-by: M.V. Hutz <git@maximhutz.me>

.gitea/workflows/ci.yml

@@ -39,6 +39,14 @@ jobs:
       - name: Run mutation tests
         run: make lint-makefile
 
+  lint-markdown:
+    name: Markdown Lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: DavidAnson/markdownlint-cli2-action@v19
+
   test-unit:
     name: Unit Tests
     runs-on: ubuntu-latest