Add documentation on how to do analysis within DST server

[lwjohnst86]

People are copying data into their own folders (which can increase our storage usage). Show them to use the Parquet files. And how to install and use my dstDataPrep package (if using R).

Stata and Parquet, doesn't seem to have the ability to import.

SAS and Parquet: https://documentation.sas.com/doc/en/pgmsascdc/9.4_3.5/casref/p0u5p2nvqu04gfn1w3zaohdfcoys.htm