Http: Change approved_ips from string to cidr validation (#3532) [BREAKING CHANGE]

* 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

homeassistant/components/emulated_hue.py

@@ -77,7 +77,7 @@ def setup(hass, yaml_config):
         ssl_certificate=None,
         ssl_key=None,
         cors_origins=[],
-        approved_ips=[]
+        trusted_networks=[]
     )
 
     server.register_view(DescriptionXmlView(hass, config))