[REF] website_profile and dependencies: improve global layout and design

Purpose is to perform a cleaning pass on website_profile templates. It
cleans the DOM, templates and CSS and proposes various improvements on
general design and layouting. This includes notably

 * lessen custom CSS and use bootstrap 4 classes;
 * simplify layout when possible;
 * make is responsive and mobile friendly;

No functional changes should occur with this commit.

Sub modules are impacted as profile is extended in various other
applications: eLearning, forum and certification.

Commit linked to task ID 1941250 and PR #31453