processed IPEDS data accessibility

[charlieeatonphd]

The processed IPEDS data file hdefa_dist20122019.dta in cell 3 of https://github.com/HigherEdData/onlinehighered/blob/main/onlineenrollmenttime.ipynb is not published in GitHub or elsewhere because it is currently too large (over 100 mb). We should reduce the data file size and publish it in the Github repo or elsewhere so that it can be downloaded via a command in the onlineenrollmenttime.ipynb Notebook.