Previously, all of the documentation was contained in a single and hard
to navigate README.md file.  This CL breaks the contents of the document
into several new files, updates the contents, and adds new information.
This information is slightly forward looking and reflects the build
layout as it will be in the next several weeks.

Test: N/A

Change-Id: I3e78290c89776d271df1006660b02825150d704b