Feature/Features-page

- [x] Replace al filler copy
- [x] Fix and tweak all feature sections for optimum size based on copy
- [ ] Render icons at new sizes
- [ ] Optimize all images
- [ ] Test & fix legacy IE

- once merged fix any responsive issues

WEBSITE-1082
please add this as a var to: https://github.com/phpbb/phpbb-website/blob/master/src/Phpbb/WebsiteInterfaceBundle/Twig/GlobalsExtension.php#L614 (without the ?from=submenu)