Implement homepage redesign

Implement the new homepage design from technical-writing#854 (closed).

Figma file: https://www.figma.com/file/e6ahJYABbB1sPT1k5s8HBp/Reorganize-docs-home-technical-writing%23854?type=design&node-id=2365-16511&mode=design&t=7ukKl21og1Rtc28a-0

Issue for content updates required for the design change: #1741 (closed)