Add helper from_package to load package datasets

[dchiu911]

Can we add a helper (e.g. from_package()) that would essentially load data in this regard:

data(dataset, package = "package_name")

I know the pipable way to do this (e.g. inside tbl_store()) would be package_name::dataset, but if we wanted to do this for github packages to get the most updated data that should be an option too. The function could wrap from_github() perhaps if we requested the get the remote version instead of local version of the package.

[rich-iannone]

This is a great idea! Will look into getting this implemented.