Port information from Slack to the Manual

[abostroem]

Slack is going to remove all conversations older than 90 days starting on Sept 1. This means that people will no longer be able to use previous conversations for help (thanks Slack). We should at a minimum propagate pinned information to the manual/set up instructions

[griffin-h]

I exported the GSP Slack workspace. At @svalenti's suggestion, I tried using slack-export-viewer to view the results, and they look pretty good. This gives us more time to get information into the manual.

[abostroem]

I made it through Apr 2020 - the download and viewer are pretty sweet