Ladybird: Add RequestServer process to optionally replace Qt Networking

LibTLS still can't access many parts of the web, so let's hide this
behind a flag (with all the plumbing that entails).

Hopefully this can encourage folks to improve LibTLS's algorithm support
:^).

Userland/Libraries/LibProtocol/CMakeLists.txt

@@ -1,16 +1,23 @@
 set(SOURCES
     Request.cpp
     RequestClient.cpp
-    WebSocket.cpp
-    WebSocketClient.cpp
 )
 
 set(GENERATED_SOURCES
     ../../Services/RequestServer/RequestClientEndpoint.h
     ../../Services/RequestServer/RequestServerEndpoint.h
-    ../../Services/WebSocket/WebSocketClientEndpoint.h
-    ../../Services/WebSocket/WebSocketServerEndpoint.h
 )
 
+if (SERENITYOS)
+    list(APPEND SOURCES
+        WebSocket.cpp
+        WebSocketClient.cpp
+    )
+    list(APPEND GENERATED_SOURCES 
+        ../../Services/WebSocket/WebSocketClientEndpoint.h
+        ../../Services/WebSocket/WebSocketServerEndpoint.h
+    )
+endif()
+
 serenity_lib(LibProtocol protocol)
 target_link_libraries(LibProtocol PRIVATE LibCore LibIPC)