Add "fast install" section to INSTALL (with new prereqs)

Updated for dev-angular merge: prerequisites now include Node.js,
npm and Bower.

User Story # 7213.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Reorder INSTALL doc sections

Detailed instructions should be linked to first.

User Story # 7213.

[ci skip]

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Merge pull request #1168 from opf/feature/updated-install-doc

Add "fast install" section to INSTALL (with new prereqs)