MAST: Tesscut doc needs updating, cloud API is no-op

[pllim]

As requested by @orionlee in #1521 (comment)

Public documentation should probably be updated, as TessCut class still have the documented
enable_cloud_dataset() and disable_cloud_dataset() methods that are essentially no-ops.

[bsipocz]

cc @snbianco

[snbianco]

Looks like the issue here is that enable_cloud_dataset and disable_cloud_datset are defined on the base class of TesscutClass, which is MastQueryWithLogin.

Some options:

1. Override the functions in TesscutClass, issue a deprecation warning, and add a :private directive to hide them from the docs.
2. Override the functions in TesscutClass and raise an exception.
3. Move the functions into the child classes excluding TesscutClass.

I'm leaning towards Option 1, but I wanted to check if there is a standard already in place for this type of thing.

[pllim]

If these are used in child classes, you could also raise NotImplementedError in the base class with a message that it should be defined in child classes. Ultimately, it is up to you, as I am unfamiliar with MAST API internals. Thanks!