Finish GitHub action

Contents (#1)

Enhancements

• Use docker image for action

Fixes

• Move Dockerfile to repository root
• Update to use poetry
• Add missing __init__ file
• Update installation path in Dockerfile

Operations

• Fix python3.10 specification
• Update coverage package
• Rename CLI and add it as a script in pyproject.toml
• Add pre-commit hooks
• Point Dockerfile and workflow to correct branches for future
• Fix context for Docker builds

Refactoring

• Rename release notes compiler to pull request description generator
• Use different environment variable name for GHA output

Other

• Add README