redo IP parsing for changed requirements

[irshadaj]

• Return all IPs in the X-Forwarded-For header
• Always return Hostname field, whether or not the X-Forwarded-For is populated
• Return all of these as a single string

The result of the parseUserIP function will be in the format:
"X-Forwarded-For: 192.168.1.1:8080,192.168.1.2,192.168.1.3; Hostname: www.google.com"

[computator]

Added comments for a few small issues.

I believe the current code is fine with IPv6 but perhaps the tests should incorporate some IPv6 addresses to prevent future regressions.

If it's helpful, the 2001:db8::/32 network for IPv6 and the 192.0.2.0/24 network for IPv4 are reserved for documentation and tests like this. https://en.wikipedia.org/wiki/Reserved_IP_addresses

The IPv6 format for RemoteAddr will be like [2001:db8::abcd:45]:12345 (I.E. URL Format. Verified here) and in X-Forwarded-For it will usually just be plain addresses such as: X-Forwarded-For: 192.0.2.25, 2001:db8::efg:23, 192.0.2.84