Update documentation for public usage

[krotscheck]

• We've spent too much time on features, and not enough on documentation. THe following documentation sections are absolutely critical for forward movement of the project:
  Run-as-a-standalone design philosophy
  Configuring database connections via java parameters (don't we support ENV here as well?)
  Deployment Models
  HA models.
  Configuration as a general topic.

Reference from kangaroo-server/kangaroo#428