* feat(channel): Manage knative eventing channels
- Support specifying the type of channel to create using --type.
- Default is to use messaging layer configuration for channels
- Channel type aliases via kn config and alias for InMemoryChannel
- User can now configure channel type aliases in kn config and specify
alias to GVK mappings for easy reference on CLI and refer with `--type` flag
- User can also use inbuilt alias 'imc' for InMemoryChannel
* Let channel reconcile, sleep for 5 secs after creation
* Add imcv1 and imcv1beta1 aliases
* Rename imcv1 alias to imc
kaustubh