Warn about the SegWit2x hard fork on our donate page

I’m not sure how easy it’ll be to get all donations sent to us during the hard fork, e.g. if they are sent to a different blockchain than the one we’re using.

Shall we disable Bitcoin donation around Nov 15 and wait until 1. things settle down a bit; 2. #13656 (closed) is solved; 3. we have pointed our bitcoin client to whatever blockchain wins?

Useful links:

• Countdown to SegWit2x
• Blockchain status

Feature Branch: web/14928-warn-about-SegWit2x

Related issues

• Related to #13656 (closed)

Original created by @intrigeri on 14928 (Redmine)