Add a few pre-commit hooks

[tapaswenipathak]

List of pre-commit hooks enabled

• [Deprecations] A quick check for the deprecated .warn() method of python loggers
• [Deprecations] A quick check on python3.6+ type annotations are present instead of type comments
• [Static Linter] Using flake8 and some other checks.
• [Linter] Running pylint
• [Code Formatter] Run Black: The uncompromising Python code formatter
• [Static Analysis] A quick static analyzer like pydocstyle static analysis tool for checking compliance with Python docstring conventions.
• [Static Analysis] A quick check to find unused Python code.
• [Security] A quick check on Python requirements for known security vulnerabilities
• [Security] Run Bandit, the tool for finding common security issues in Python code
• [Security][Python Project Dependencies] Enabling something like, skjold to check for Security audit Python project dependencies against security advisory databases
• [Code Organizer] Run a Python import rewriter for ex: zimports
• [Production Server Cleaning] A quick check for debugger statements and py37+ breakpoint() calls in python source.

Tasks

• [x] Document how to enable in django-on-docker
• [x] Update requirements.txt