Add initial How to Build with Stuart DocumentAdds a new document that comprehensively describes how to manuallyset up a build environment using Stuart.Covers the following topics:1. Pre-requisites - Git, Python, compilers, SDKs, etc.2. Initial steps - Cloning the repo, set up Python virtual env, etc.3. Stuart command explanation and corresponding examples4. Common developer scenarios with examples showing what to do5. Common questions section with answersStuart presents a relatively consistent interface to build mostcontent in edk2 so this document is meant as a long-term startingpoint for new contributors to understand the basics of using Stuartfor various areas they are working in within edk2.Cc: Sean Brogan <sean.brogan@microsoft.com>Cc: Michael D Kinney <michael.d.kinney@intel.com>Cc: Liming Gao <gaoliming@byosoft.com.cn>Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>