content.php: *Now pulling data from new file connection.php and constants.php
includes/connection.php: *New file for connecting to MySQL database
includes/constants.php: *New file containing MySQL config settings.
includes/footer.php: *Updated with code to disconnect database connection after the page has loaded.
src/content.php: *Set sidebar to pull in navigation elements from MySQL database. Added class "selected" to nav link for the current active page. Set content section to display text depending on URL parameters.
src/includes/functions.php: *Added new functions for database queries for navigation links on content.php.
src/sass/base/_palette.scss: *Updated styles of #navigation section.
src/styles/main.css