Mainification: Bring Onboarding in from rh-test (#6564)

## Summary

Migrate the onboarding / login / sign-up / survey pieces from `rh-test`
to `main`.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6564-WIP-Bring-Onboarding-in-from-rh-test-2a16d73d365081318483f993e3ca0f89)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Jin Yi <jin12cc@gmail.com>
Co-authored-by: GitHub Action <action@github.com>

src/platform/remoteConfig/types.ts

@@ -14,7 +14,6 @@ type ServerHealthAlert = {
  */
 export type RemoteConfig = {
   mixpanel_token?: string
-  require_whitelist?: boolean
   subscription_required?: boolean
   server_health_alert?: ServerHealthAlert
 }