Add HTTP & SOCKS5 proxy support (#4321)

This can be configured using the `CHATTERINO2_PROXY_URL` environment variable.
The behaviour is similar to curl's CURLOPT_PROXY

src/providers/liveupdates/BasicPubSubManager.hpp

@@ -4,6 +4,7 @@
 #include "common/Version.hpp"
 #include "providers/liveupdates/BasicPubSubClient.hpp"
 #include "providers/liveupdates/BasicPubSubWebsocket.hpp"
+#include "providers/NetworkConfigurationProvider.hpp"
 #include "providers/twitch/PubSubHelpers.hpp"
 #include "util/DebugCount.hpp"
 #include "util/ExponentialBackoff.hpp"
@@ -336,6 +337,8 @@ private:
             return;
         }
 
+        NetworkConfigurationProvider::applyToWebSocket(con);
+
         this->websocketClient_.connect(con);
     }