Document and automate deployment process

[nlam-grok]

The following commit aims to add a simple script for installing dependencies and running the server. The README has also been updated with instructions on how to do a deployment. This documentation is aimed at any new NCSS tutor who may need to set up the server again in the future.

[joelgibson]

This change is now a bit out-of-date since switching from Flask to Starlette - I've left instructions on how to install and run at https://github.com/ncss/necsus#installation, and perhaps the information on how to reverse-proxy belongs elsewhere?

I did notice that with how I've set up reverse proxying, the IP logging is wrong (everything looks like it comes from localhost). I'll try to figure out how to log the X-Forwarded-For header (which I assume Caddy adds when reverse-proxying). Aside from this, the reverse proxy and auto-HTTPS worked great with Caddy.