TrustProxies should be configurable

[kolaente]

Before #38295, the TrustProxies middleware was configurable via an env variable. We dynamically deploy instances of our applications for each PR with docker behind a reverse proxy. Because of this, the IP of the proxy is not known before deploying the application and does not match the IP configured in the TrustProxies middleware. This leads to broken URLs (The proxy does TLS termination). To "fix" this we resorted to setting $proxies = '*' in the middleware which kind of defeats its whole purpose.

I propose to make the middleware configurable again. However, I guess the removal of the configuration option was intentional, therefore a discussion might be needed.
I could send a PR to add this back in.

[amenk]

It's configurable now, but there is no default ENV variable, still

framework/src/Illuminate/Http/Middleware/TrustProxies.php

Line 50 in edde9ab

$trustedIps = $this->proxies() ?: config('trustedproxy.proxies');

PR: #41322