docs(client): the big docstring refactor

This refactors the client docstrings such that they provide more useful information to the user. Please note that I also refactored how `clusters:create` is parsed as part of a nitpicking (breaking backwards compatibility for the command), but I can easily revert that if the change is unnecessary. This PR should be completely backwards compatible, save the `clusters:create` change.
This came directly from above a couple of lines. I agree and I can revert to your proposal, but could we try elaborating a bit more on "requiring wildcard DNS configuration"? Maybe the following: `Note: this requires wildcard DNS configuration on the domain. For example, a <domain> of deisapp.com requires *.deisapp.com`?