cluster overrides needs documentation

[bcle]

I suggest first adding it to the Concepts article, or linking from there.

Aha! Link: https://pf9.aha.io/features/ARLON-379

[cruizen]

@jayanth-tjvrr Do we have no docs for cluster overrides so far? - or is it part of some page that's not accessible from the published docs?

[cruizen]

Hey team! Please add your planning poker estimate with Zenhub @bcle @jayanth-tjvrr @Rohitrajak1807 @ShaunakJoshi1407