[landing] redesign footer component

Summary:
This is the second part to implmenenting the redesign for the footer component. This diff adds the new elments that are shown in the figma design (screenshot below) and arranges them to match the design

Depends on D8082

Test Plan:
Please watch the demo video/see the screenshots below:

Desktop/Responsive:

Tablet:

Mobile:

Reviewers: atul, kamil

Reviewed By: kamil

Subscribers: ted, ashoat, tomek

Differential Revision: https://phab.comm.dev/D8083