Proper documentation for initContainer

[manusa]

Now in order to avoid initContainer you just need to exclude the enricher as @kuailexingmao suggested.

@rohanKanojia Can this be done in gradle.properties when using the gradle plugin?

Originally posted by @timemanx in #1179

[ash-thakur-rh]

Created PR: #3847 for improving docs for jkube-volume-permission enricher.