[Docs] Fix outdated docs for standalone cluster

This is now supported!

Author: andrewor14 <andrewor14@gmail.com>
Author: Andrew Or <andrewor14@gmail.com>

Closes #2461 from andrewor14/document-standalone-cluster and squashes the following commits:

85c8b9e [andrewor14] Wording change per Patrick
35e30ee [Andrew Or] Fix outdated docs for standalone cluster

(cherry picked from commit 8af2370619a8a6bb1af7df43b8329ab319348ad8)
Signed-off-by: Andrew Or <andrewor14@gmail.com>