Migrate the example download from custom implementation to `ansys-tools-common`

Hi! I noticed that you are using a custom implementation to download examples from [example data](https://github.com/ansys/example-data) repository.

I suggest you to remove this implementation and use the implementation from [PyAnsys common tools](https://tools.docs.pyansys.com/version/stable/user_guide/ansys_downloader.html). The implementation is easily replaceable and it will save you maintenance work 🙂