Move update.sh and send_update.py into the repo

[ethteck]

Move all the specific stuff into env vars and load them and do good stuff

[mkst]

A question off the back of this is whether we create a separate "deployment" repo which contains these scripts, the production docker compose files etc... I am not sold on whether it's worth it at this point in time (there's not that much 'config' in this repo). But just throwing it out there :)