Move most of the CRD documentation currently under 'tasks' to 'concepts'

**This is a Feature Request**

While discussing a CRD feature promotion blog post, @sftim [noticed](https://github.com/kubernetes/website/pull/35459/files#r943854829) that we're primarly documenting CRD in the "tasks" section of the documentation, but most of the documentation is about CRD concepts, which are [underdocumented](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/) in concepts.

**What would you like to be added**

I would like find a way to reorganize the content.

**Why is this needed**

Make information about CRDs easier to find.
Improve consistency of documentation.

Start by reviewing the CRD documentation under the tasks section and the existing concepts page at concepts/extend-kubernetes/api-extension/custom-resources/. Identify which material explains concepts rather than procedures, then reorganize it so CRD information is easier to find and the concepts and tasks sections are consistent.

Written by the indexing model from the issue text.