Adding initial environments user guide
Fixes #6986: adding Bastion developer install documentation.

When the bastion documentation was moved to the katello.org
repository we neglected to move the bastion setup instructions.
This commit adds the missing documentation.

http://projects.theforeman.org/issues/6986
Merge pull request #26 from waldenraines/6986

Fixes #6986: adding Bastion developer install documentation.
Merge pull request #7 from parthaa/env

Adding initial environments user guide
fixes #7161 - correctly referencing grunt-cli
Merge pull request #27 from komidore64/rmi7161-bastion-dev-page-grunt-cli

fixes #7161 - correctly referencing grunt-cli
Refs #7202: Add splash page to announcement incoming changes.