Improve "website" purchase process

[moon69]

TL;DR

"Website" purchase of Space Age was frustrating

What ?

Ideally: automate "Factorio website" purchase so I don't need to be logging into 3rd party websites with unspecified login credentials
Minimally: Indicate on https://factorio.com/buy-space-age that:

• you will actually be buying from HumbleBundle
• not to freak out after purchase when the "Your Factorio: Space Age order is ready" email from HumbleBundle takes you to a "Key already claimed" page
• you have to login to humblebundle.com with the same email address as your Factorio account
• you have to look in your HumbleBundle profile to get a key, then go to Factorio website → Profile → Memberships → Input Upgrade Code (this information is not provided if you copy your key from HumbleBundle → Profile → Library)

Why ?

See TL;DR