KEP-4292: Add custom profiling in kubectl debug (#4293)

* KEP-4292: Add custom profiling in kubectl debug

* Typos, explanation and refactorings

* Add correct feature gate

* Add more details in KEP after review

* Gofmt to code example

* Make changes based on PRR review

Author: ardaguclu

keps/prod-readiness/sig-cli/4292.yaml

@@ -0,0 +1,6 @@
+# The KEP must have an approver from the
+# "prod-readiness-approvers" group
+# of http://git.k8s.io/enhancements/OWNERS_ALIASES
+kep-number: 4292
+alpha:
+  approver: "@johnbelamaric"