Update Readme

[drey-bigney]

As a maintainer of the OSMT project, I want to update the README so that a user who is technically proficient but not necessarily familiar with OSMT can follow the documentation in order to build, install, and configure the tool.

While we do have some documentation, we want to ensure that the documentation is complete, clear, and well organized. Suggested outline is as follows:

• Overview
• Architecture
• • Dependencies
• • • Elasticache
• • • Redis
• • • MySQL
• • • Okta
• Build
• • Requirements (Docker, Java11, etc)
• Install / Run
• • Configuration
• • Running Locally
• • Production Installation
• • Post-installation (BLS, O*NET, etc)
• How to get help