CheCluster API v2 language review for CheCluster Custom Resource fields reference

Language review of the source files used for single-sourcing https://www.eclipse.org/che/docs/stable/administration-guide/checluster-custom-resource-fields-reference/, for the v2 version.

Consider reviewing directly in this pull request https://github.com/eclipse-che/che-operator/pull/1324 the file api/v2/checluster_types.go
https://github.com/eclipse-che/che-operator/pull/1324/files#diff-10f5235ef9752eb68e9938878907ee064b366dd04540ac315d0b8912860a38dc The comments are the documentation.

If we start working on this after the merge of this pull request, review for language the comments in the api/v2/checluster_types.go in the https://github.com/eclipse-che/che-operator/ repository.