Add support for e-signature on member agreements.

[ergodone]

Legally recognized electronic-signatures have requirements for document retention, user identification, and other requirements depending on the country. Specifically in the USA there is the need to sign liability waivers.

We'd like to see support for legally binding contracts via an e-signature. I believe e-signature requirements are similar in many countries. Overview of legal requirements for many countries can be seen here:
https://www.docusign.com/products/electronic-signature/legality/australia

Many e-signature services provide APIs for having documents signed at reasonable prices. For our maker space we have less than 10 sign ups per month. So these services would be affordable and remove the burden of on-going document management. Using a independent 3rd party service would help to ensure the legal requirements are met:

https://www.signwell.com/ has a free tier upto 25 signatures/month.

esignatures.io has a per-signature pricing model (USD $1) and discounts for non-profits.

Anvil has a free tier with pay-per-signature after that but I'm unclear if it does document retention on the free tier:
https://www.useanvil.com/
https://github.com/anvilco/python-anvil

[proffalken]

Following on from a recent event that occurred where the terms of joining weren't clear, I'd also like to see this to remove any ambiguity over membership

[jabelone]

Sorry I never commented on this one, love this idea! It's related to #208 and would require that one to be implemented first. Once we're generating membership agreements, we could then integrate a document signing system to "sign" them.

[rechner]

I've started experimenting with https://github.com/docusealco/docuseal at our space this week for membership agreements and liability waivers, so far it seems to be working well. Opensource Docuseal has just enough API to look up a signing party by email so might work that way. Annoyingly docuseal is dual license and puts some features like the embedding API behind a $20/month/user license.