Add the ability to copy datasets

[reesercollins]

There is currently no way for users to copy datasets in superset. Even though they can copy the SQL of a dataset, any changes we make to the field types (e.g., in cases where we turn long, complex types into JSON, or advanced types as described in #17852) cannot be easily copied.

Here's what I propose:

Add a duplicate action to virtual datasets within the dataset list:

When clicked, it will open a modal which will allow the user to choose a name for the new dataset:

When OK is clicked, a duplicate of the dataset is created with the chosen name.

Here it is in action:

2022-06-01.15-40-22.mp4

See #20309 for demo

There was a SIP created for this, but I have been advised the changes are so small, it may not require one.