Adapt installation guide with current requirements

- Update naming where it makes sense
- Fix a few spelling and phrasing issues

Change-Id: If08a7c77a35624adfdaafc276850b6d896356441
Signed-off-by: Dan Kalowsky <daniel.kalowsky@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
11 files changed