Introduce Pipenv

Replace requirements.txt with pipenv for consistent development environments. Pipenv maintains a superior Lockfile similar to NPM. Added additional development dependencies and mypy configuration.

This contains a package update too:

• alembic from 1.12.1 to 1.13.2
• flask from 3.0.0 to 3.0.3
• SQLAlchemy from 2.0.23 to 2.0.31

Dockerfile

@@ -5,7 +5,6 @@ WORKDIR /app
 EXPOSE 5000
 
 # First, copy and install only the requirements...
-ENV PIPENV_VENV_IN_PROJECT=1 
 RUN pip install --upgrade pip setuptools
 RUN pip install pipenv
 COPY Pipfile.lock .