chore: monthly updates for July'23

- migrate to `pdm` from `poetry`
- update dependencies
- improvises `dockerfile` (drops `containerfile`)
- only `python` & `pip` are required in ci/cd
- adds `compose.yml`
- simplifies local & containerized development

.github/workflows/testing.yml

@@ -18,9 +18,7 @@ jobs:
           python-version: "3.11"
       - name: Install dependencies
         run: |
-          curl -sSL https://install.python-poetry.org | python -
-          export PATH="$HOME/.poetry/bin:${PATH}"
-          poetry install
+          python -m pip install --user --no-cache-dir -r requirements.txt
       - name: Run unit tests
         run: |
-          poetry run python -m unittest discover
+          python -m unittest discover