[Tracking] IA redesign

[femmebot]

Moved to https://github.com/github/classroom/issues/32

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IA redesign updates based on these priorities. Refer to this IA redesign Figma file for UI details/context.

• New header / navigation: Shipped
  • Issue: Create a copy of the header/layout which is new/old based on the redesign feature flag #2353
  • PR: https://github.com/github/classroom/pull/49
• Update Settings content layout: Shipped
  • Issue: Update Settings content/layout (IA redesign) #2496
  • PR: https://github.com/github/classroom/pull/58
• Update Admins/TAs content layout: Shipped
  • Issue: Update Admins/TAs content layout (IA redesign) #2495
  • PR: https://github.com/github/classroom/pull/76
• Update Roster management:
  • Issue: Update roster management (IA redesign) #2497 https://github.com/github/classroom/issues/35
  • See earlier work: Move RosterEntry update to background job Moves RosterEntry update to background job #2233
  • PR:
  • Description:
    • Improved ability to search/sort roster entries for large classes
    • Updating roster management via modal
    • Layout/UI updates
• Update Assignment creation and Assignment view pages
  • Issue: Assignment create (individual, group), view, listing pages (IA redesign)  #2506 https://github.com/github/classroom/issues/89
  • PR:
• Student page view (new page with new functionality)
  • Issue:
  • PR: