pybricksMicropython/lib: replace parser

This replaces the Python parsing library. The python-ast package has
really poor performance (many seconds to parse a 500 line file). The
new package can parse a file about 100 times faster.

src/pybricksMicropython/lib.test.ts

@@ -96,6 +96,17 @@ from .r import x
 from ..r import x
 from ...r import x
 from ....r import x
+
+# import q
+# from q import q
+"""
+import q
+from q import q
+"""
+'''
+import q
+from q import q
+'''
 `;
 
     const modules = findImportedModules(script);