More gov-2.0 compliant

• Added minimization for css to webpack.
• Made sample page as a part of ditribution.
• Removed inverse navbar from sample page.
• Updated links in sample doc to point to dist folder(for easier testing)
• navbar/nav changed BG to #38598A. Changed link text decoration
• buttons change the background colour to #38598A for the default and primary, and text colour to white.
• Pills change the background colour to #38598A
• Progress bars Basic and animated background colour changed to #38598A
• List groups & Primary Panels: background colour changed to #38598A and text white.