Add missing Apache 2.0 licensing elements

See https://developer.gov.bc.ca/docs/default/component/bc-developer-guide/use-github-in-bcgov/license-your-github-repository/#apply-the-licence-to-your-project

> Use the following boiler-plate text in the comments header of every source code file, as well as the bottom of your README.md:
>
> Copyright 2019 Province of British Columbia
>
>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.

Start by listing the repository's source code files and locating README.md. Add the supplied Apache 2.0 boilerplate to each source file's comment header and to the bottom of README.md. Done means all source files and the README contain the specified licensing text.

Written by the indexing model from the issue text.