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/twitch/PubSubManager.cpp

@@ -1,6 +1,7 @@
 #include "providers/twitch/PubSubManager.hpp"
 
 #include "common/QLogging.hpp"
+#include "providers/NetworkConfigurationProvider.hpp"
 #include "providers/twitch/PubSubActions.hpp"
 #include "providers/twitch/PubSubClient.hpp"
 #include "providers/twitch/PubSubHelpers.hpp"
@@ -514,6 +515,8 @@ void PubSub::addClient()
         return;
     }
 
+    NetworkConfigurationProvider::applyToWebSocket(con);
+
     this->websocketClient.connect(con);
 }