Script to automate RTD config file update

[eirikurj]

Purpose

This PR adds an initial script that can be used to automate the update of RTD config files for a number of our repositories. The idea is to minimize the maintenance needed managing this particular file until some other solution, such as templating, is supported (see https://github.com/mdolab/private-docs/issues/298 for some discussion). If not, we could improve on this later by automatically generating the yaml file.

Expected time until merged

No rush

Type of change

• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (non-backwards-compatible fix or feature)
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no API changes)
• [ ] Documentation update
• [ ] Maintenance update
• [ ] Other (please describe)

Testing

Checklist

• [ ] I have run flake8 and black to make sure the Python code adheres to PEP-8 and is consistently formatted
• [ ] I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• [ ] I have run unit and regression tests which pass locally with my changes
• [ ] I have added new tests that prove my fix is effective or that my feature works
• [ ] I have added necessary documentation

[marcomangano]

If no one else has comments, I will merge this tomorrow morning.