Python: add lsp configuration widget

Change-Id: I688981293e3bbbee64fc2d714146fcdfa8126458
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/python/pythonlanguageclient.h

@@ -57,6 +57,8 @@ public:
     LanguageClient::Client *createClient(LanguageClient::BaseClientInterface *interface) const final;
 
 private:
+    static QJsonObject defaultConfiguration();
+
     QString m_interpreterId;
 
     PyLSSettings(const PyLSSettings &other) = default;