Add support for client-side dry-run capabilities in `client.create()`

[theoctober19th]

Right now, the dry_run arg to Client.create() method is a boolean, which stuffs --dryRun=All argument to the K8s request. This is fine for the server-side dry run.

However, there are often times when a client-side dry-run is desired. It would be awesome if we could add a functionality to support this. Maybe we can make dry_run an enum, with three values False, Client and All. I'm open to other ideas as well.

If this is worth adding, I'm happy to contribute with a pull request as well!

[gtsystem]

The problem with client side dry_run is that it's not so easy to implement, because all write methods need to return the created/modified resource. Which means, we would need extra business logic on the client side to perform all actions usually done by the server (for example to apply a patch)..