Document how to modify kata availability on a cluster after the initial installation (i.e. install kata on additional nodes) or remove kata from node(s))

This ticket tracks documenting how users can modify kata availability on a cluster after the initial installation 

1. Install kata on additional node(s)
2. Remove kata from node(s)). 

 This is done by opening the kataConfig resource and editing the kataconfig poolselector spec.

Link to recording: https://drive.google.com/open?id=10e6wuKii8PdGHWB7Rq6t6gLIylda_VDt

Pavel's write-up of the changes: https://docs.google.com/document/d/18gm0ICiFO4Dy5pjSfG8yR1COO1pmPV8jCoKpnZwvGIw/edit