Allow overriding config with ENV (Grasscutters#506)

Allow overriding config with ENV (handy when running with docker or debugging without modifying script)
Also log proxy config for easier debugging (when sharing screenshots)

proxy_config.py

@@ -1,4 +1,17 @@
+import os
+
 # This can also be replaced with another IP address.
 USE_SSL = True
-REMOTE_HOST = "127.0.0.1"
-REMOTE_PORT = 443
+REMOTE_HOST = "localhost"
+REMOTE_PORT = 443
+
+if os.getenv('MITM_REMOTE_HOST') != None:
+    REMOTE_HOST = os.getenv('MITM_REMOTE_HOST')
+if os.getenv('MITM_REMOTE_PORT') != None:
+    REMOTE_PORT = int(os.getenv('MITM_REMOTE_PORT'))
+if os.getenv('MITM_USE_SSL') != None:
+    USE_SSL = bool(os.getenv('MITM_USE_SSL'))
+
+print('MITM Remote Host: ' + REMOTE_HOST)
+print('MITM Remote Port: ' + str(REMOTE_PORT))
+print('MITM Use SSL ' + str(USE_SSL))