Change default jwt name

[bilbofroggins]

It's just called 'token', which might be fine if you are running this app by itself on a server... but I run this app along with a bunch of others. Having something called just 'token' is not descriptive enough to know which app it is a part of and can eventually lead to overwriting if another app makes this same mistake. Please namespace the jwt

[dullage]

Fair point. This wasn't considered when custom path prefixes were introduced (allowing flatnotes to share a domain). I'll put this on the to-do list for the next batch of changes.