* Change approved_ips from string to cidr validation
Relabel to trusted_networks, better reflecting its expected inputs,
everything that ipaddress.ip_networks recognizes as an ip network
is possible:
- 127.0.0.1 (single ipv4 addresses)
- 192.168.0.0/24 (ipv4 networks)
- ::1 (single ipv6 addresses)
- 2001:DB8::/48 (ipv6 networks)
* Add support for the X-Forwarded-For header
