Clarify Installation Instructions

[carpepraedam]

Description

The repo root level README includes directions how to install theproject.

It is outdated (references moving common.py to settings, but it is already there) and has misleading paths.

Update the README to include the current step-by-step requirements to install. The first step should be to clone the repo. Include all steps and commands required in the correct order in order to successfully clone, create a venv, activate a venv, install dependencies, makemigrations, migrate, and runserver.

[lloydbrian]

#89 pull request to address path of requirements.txt has been addressed and filename for settings_private.py has been corrected. @carpepraedam this was done via the public forked repo. Private forked repo pull request - I can't seem to work. I will look into it tomorrow as well.