[Documenation] Build out documentation site

[grovesy]

Build out documentation website

Either through markdown files or pydoc / similar there should be a set of documentation for a github-proxy version

To start with we should document the configuration options

Databases

file vs mongo configuration

Authentication

Local vs AD

Default repos

How to add default repos

User Manager -

Local

1. adding new users
2. deleting user
3. linking git-accounts with users

Kerberos