search is dotcom (feature branch)

Created by: limitedmage

Figma design

This is the feature branch for the "Search is .com" project. All work for that project will go in here when merging PRs so it can be checked in together.

This PR will contain all work from PRs that resolve the subtasks of #23723 (closed), in addition to #23725 (closed). Once all sub-tasks are completed and checked into this branch, this PR will be updated from "Draft" to "Ready to review", but hopefully no extensive review will be necessary since all the sub-tasks will be reviewed already.

• Reorganize homepage code (#23868)
• Update navbar (#23862)
• Update subtitles under logo and video (#23865)
• Add main marketing section (#24015)
• Update repogroups section (#23929)
• Add self-hosted section (#23946)
• Add customers sections (#23987)
  • Fix logo image alignment (Issue: #24016 (closed); PR: #24025)
• Update footer (#24001)
• Remove old sign up CTA (#23868)
• Add metrics (Issue: #23922 (closed))
  • Metrics for main marketing section (#24015)
  • Metrics for selfhost section (#23946)
  • Metrics for customers section (#23987)
  • Metrics for footer (#24001)
• Remove redirect (Issue: #23725 (closed); PR: #23983)
• Address final polish items (#24053)

Closes #23723 (closed) Closes #23725 (closed) Closes #23922 (closed)

BLOCKERS:

• Final hero graphic (dark mode has wrong background color) [Owner: @rrhyne]
• Add Source Sans Pro font to design system under variable --marketing-font and update marketing hero and customers sections to use it [Owner: @sourcegraph/frontend-platform to add font, @limitedmage to update hero & customers sections; issue: #24017 (closed)]
• Add Cloud vs Self-host docs page [Owner: @sourcegraph/core-application]

Note on CTAs:

The CTA work (Issue: #23923 (closed), PR: #24027) will not be merged into this branch; it'll be merged separately and deployed on Thursday by @lguychard.