Add a script to create provider API script template

[obulat]

Fixes WordPress/openverse#1734
This script will make it easier for new contributors to add provider API scripts by giving them a Cookiecutter-like script for writing Provider API scripts. It creates the skeletons of the script, workflow file and tests.

To run the script, create and activate a virtual environment, navigate to the templates folder and run it with provider name as a parameter:

cd src/cc_catalog_airflow/templates/
python3 create_api_script.py <provider_name>

This will create three files:

1. The API provider script with a skeleton implementation
2. The test file (blank)
3. The workflow file which doesn't really need much change, I suppose.

There are some instructions and a lot of #TODO comments in the file.

This PR contains all the changes from #93, that I accidentally merged into licenses branch instead of main.

Signed-off-by: Olga Bulat obulat@gmail.com