feat: add support for rotating jwt keys This allows jwt_secret to have multiple ',' separated secrets. The first/leftmost should be used to sign new JWTs. All of them are used (starting from left/newest) to try to verify a JWT. If the first secret is < 32 chars in length JWTs are disabled. If any of the other secrets are < 32 chars, the configuration code causes the software to exit. This prevents insecure (too short) secrets from being used. Updated doc examples and tests.

#!/usr/bin/env python

# Roundup requires Python 2.7+ as mentioned in doc\installation.txt
from __future__ import print_function
import sys

VERSION_NEEDED = (2, 7)

if sys.version_info < VERSION_NEEDED:
    print("Content-Type: text/plain\n")
    print("Roundup requires Python %s.%s or newer." % VERSION_NEEDED)
    sys.exit(0)