Move various testbed-related docs to shared Drive folder

I created a [**GA4GH Testbed**](https://drive.google.com/drive/u/1/folders/1QNd5LD61Uoc2j6-rRgR_wPykWxgMLsxr) folder in Google Drive to collect and organize all the docs, slides, etc. we have floating around for the testbed. I moved most of the relevant files that I own, but need some help from others (doc owners tagged below).

These are the obvious candidates based on an initial search (but feel free to add others):
+ [20190517 - GA4GH Testbed Orchestrator Design - v1](https://drive.google.com/open?id=1Cl3EZ5B1V-nxEeUCOJKyTHHJRDhknJyopdtjNcq_7jI) ~ @briandoconnor
+ [Testbed UI](https://drive.google.com/open?id=13DIHDPSbpSeXVfwjIYmbn4BMiipPNrY5ZbBb03QMi1M) ~ @jb-adams
+ [2019-09 Testbed Mini-Hackathon](https://drive.google.com/open?id=1-BJuGT1TSv53uQKQYr84oEY1APqa-4YloUw6n6jRHCQ) ~ @rishidev
+ [GA4GH Testbed Ideas and Meetings (Search+DURI+WES+DRS)](https://drive.google.com/open?id=1M9pF1tATEOXKb3XapO319Zo3tHNuGC_QiTjm7rauI_4) ~ @dglazer
+ [Workflow Portabilty and GA4GH - RFC](https://drive.google.com/open?id=1y--yeRGsmV2zGiytFgattddFh9e763UIvWTiQDDj7zQ) ~ @briandoconnor