Page formatting refactor

Updated the page header and footer to reflect a new structure, with 4
container divs in total:
 - page_Container - the whole page
 - page_Header  - the header
 - page_Body - the page body
 - page_Footer - the footer

Also removed a redundant and misleading method from sql.php
(createUser) as it was very outdated and superseded by functionality
implemented recently.