Install --wait

[kensipe]

This was partially implemented on #966 but needs the following:

we need wait for more than just install. So we should have a separate function for wait on a plan.
the wait should be part of the kudo.Client allowing it to be used as a lib... for instance for terraform
It is likely we need to change the timeout for waits (I was initially thinking timeout was defined when acquiring a kudo.Client but I can see wait requiring it for each invocation.
the wait should work for an update, the code for terraform provide is a good start: https://github.com/runyontr/terraform-provider-kudo/blob/master/kudo/resource_kudo_instance.go#L547-L576. however it doesn't work well for update. It needs to check the meta.generation to verify that the plan actually started. Without the meta.generation it is possible that the "last plan" is "finished" and that is the wait func view of the world... which is incorrect.
To narrow the scope... we are not looking for wait to work with upgrade and update... just that the solution should have that in mind and provide a solution that can be leveraged.

more details are likely on the #966 PR