Change public accounts pages to mount the web UI (#19319)

* Change public accounts pages to mount the web UI

* Fix handling of remote usernames in routes

- When logged in, serve web app
- When logged out, redirect to permalink
- Fix `app-body` class not being set sometimes due to name conflict

* Fix missing `multiColumn` prop

* Fix failing test

* Use `discoverable` attribute to control indexing directives

* Fix `<ColumnLoading />` not using `multiColumn`

* Add `noindex` to accounts in REST API

* Change noindex directive to not be rendered by default before a route is mounted

* Add loading indicator for detailed status in web UI

* Fix missing indicator appearing while account is loading in web UI

yarn.lock

@@ -9663,11 +9663,6 @@ regjsparser@^0.8.2:
   dependencies:
     jsesc "~0.5.0"
 
-rellax@^1.12.1:
-  version "1.12.1"
-  resolved "https://registry.yarnpkg.com/rellax/-/rellax-1.12.1.tgz#1b433ef7ac4aa3573449a33efab391c112f6b34d"
-  integrity sha512-XBIi0CDpW5FLTujYjYBn1CIbK2CJL6TsAg/w409KghP2LucjjzBjsujXDAjyBLWgsfupfUcL5WzdnIPcGfK7XA==
-
 remove-trailing-separator@^1.0.1:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/remove-trailing-separator/-/remove-trailing-separator-1.1.0.tgz#c24bce2a283adad5bc3f58e0d48249b92379d8ef"