Method for getting all known datasets

[d-chambers]

ObsPlus.DataSet should have a class method for getting names and descriptions of all the known datasets, optionally including those on PyPi. I am thinking something like this:

import obsplus

ds_info = obsplus.DataSet.get_dataset_menu() 

ds_info is a dataframe with columns:

• name: The name of the dataset (str)
• description: The description of the dataset (str)
• source: Either the source path (if downloaded) or "pypi" if not yet installed (str)
• data: data path, if the data have been downloaded or empty (str)