[REFACTOR][PY] Establish tvm.te and tvm.driver (#4900)

- Move the related files to tvm.te
- Move build_module.py to tvm.driver
diff --git a/python/vta/build_module.py b/python/vta/build_module.py
index f368362..4a62d35 100644
--- a/python/vta/build_module.py
+++ b/python/vta/build_module.py
@@ -96,7 +96,7 @@
     --------
     tvm.lower : The original TVM's lower function
     """
-    cfg = tvm.build_module.current_build_config()
+    cfg = tvm.target.BuildConfig.current()
     if not cfg.add_lower_pass:
         with build_config():
             return tvm.lower(*args, **kwargs)
@@ -113,7 +113,7 @@
     --------
     tvm.build : The original TVM's build function
     """
-    cfg = tvm.build_module.current_build_config()
+    cfg = tvm.target.BuildConfig.current()
     if not cfg.add_lower_pass:
         with build_config():
             return tvm.build(*args, **kwargs)