Update functions.php for Caddy

[lilrags16]

This change gets the left most IP address from the X-Forward-For header. This is required to get the right IP easily from Caddy. Tested and working.

[github-actions]

Hello & Welcome! :)

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[lilrags16]

@johnnyq what is the process for getting PRs included upstream?

[git-kup]

@johnnyq what is the process for getting PRs included upstream?

https://docs.itflow.org/contribute

[johnnyq]

how will this affect users not using Caddy?

[lilrags16]

If someone is using the CONST_GET_IP_METHOD == "HTTP_X_FORWARDED_FOR" value in there config, it will always set the IP that ITFlow logs as the leftmost IP presented in a list of comma separated IPs.

Case 1 - Not using config value, not using caddy- No changes to use
Case 2 - Using config value, but reverse proxy only passes on IP: No effective change as the left most of a list of one is still the same
Case 3 - Caddy w/ Value set: The actually client IP is passed through correctly.