Provide guidance for setting KUDO controller resource reservations

_As discussed in KUDO community meeting 2019-07-25 (see minutes [here](https://docs.google.com/document/d/1UqgtCMUHSsOohZYF8K7zX8WcErttuMSx7NbvksIbZgg/edit#))_

As a KUDO operator user, I want to understand what memory requests/limits I should set so that my KUDO operators deploy successfully given the number and scale of operators I need to deploy.

As a starting point:

1. What is mem profile at idle?
1. What is mem profile with 1-5 operators?
1. What is mem profile for dozens or hundreds of operators?

(thanks to @kensipe for helping define this problem!)

The issue names no repository files or tests; start with the linked KUDO community meeting minutes and identify the controller resource settings and measurement entry points. Document memory usage at idle and with 1–5, dozens, and hundreds of operators, with guidance for choosing requests and limits.

Written by the indexing model from the issue text.