Add license headers to code files

[svrnm]

The apache license requires to have a license header added to each file covered by that license. Here the py files should contain a license header at the top of the file like the following:

# Copyright 2023 Cisco Systems, Inc. and its affiliates
#
# 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.
#
# SPDX-License-Identifier: Apache-2.0

[adchella-te]

Added the apache license header to the python files.