Create settings options for new IA pages

Summary

In order to better track the pages needed for the new IA we need to offer the option for admins to configure them in the backend (same as we currently do fo Act/Expore).

Requirements

• This feature should be hidden and revealed/enabled by the new IA feature flag from PLANET-7044. On activation the settings below should be revealed and the old ones under Navigation (Act, Explore, Issues) should be hidden.
• Create 3 dropdown settings under Planet 4 > Analytics
  • Select "Get Informed" page
  • Select "Take Action" page
  • Select "About Us" page
• The dropdown menus should show all pages.
• The first option (default) should be blank.
• Based on those selections, adjust the dataLayer pageType variable (instead of "Default page"):
  • Get informed > "Get Informed Page"
  • Take Action > "Take Action Page"
  • About us > "About Us Page"
• Update special pages test