Moving section from style guide to other chapters

Moved 2 sections to Introduction.

Moved 1 section to Setting up/Creating Restructured Text.

Issue-ID: DOC-670

Change-Id: I2b147d7e54f1b8e5f10521734b86531e66ad2c68
Signed-off-by: Andrea Visnyei <andrea.visnyei@nokia.com>
3 files changed