Python: add create venv action

The action can be triggered from the interpreter chooser of the editor
toolbar.

Change-Id: Ie23b68a3790525ea02883ef359b357a0d317b2f5
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/python/pythonutils.h

@@ -16,4 +16,8 @@ QString pythonName(const Utils::FilePath &pythonPath);
 class PythonProject;
 PythonProject *pythonProjectForFile(const Utils::FilePath &pythonFile);
 
+void createVenv(const Utils::FilePath &python,
+                const Utils::FilePath &venvPath,
+                const std::function<void(bool)> &callback);
+
 } // Python::Internal