Move model code from Rust monorepo to improve Rust compile times

This will need work done to support w2l.

models-from-rust-monorepo/tts/nemo/utils/exceptions.py

@@ -0,0 +1,19 @@
+# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class NeMoBaseException(Exception):
+    """ NeMo Base Exception. All exceptions created in NeMo should inherit from this class"""
+
+    pass