BaseTools: Add YAML files with path env and tool extdeps

https://bugzilla.tianocore.org/show_bug.cgi?id=2315

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

BaseTools/Source/Python/basetool_tiano_python_path_env.yaml

@@ -0,0 +1,11 @@
+## @file
+# Add this folder to the pypath so modules can be easily
+# loaded
+#
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+{
+  "scope": "global",
+  "flags": ["set_pypath"]
+}