Zoomaker

[Refactor Zoomaker to skip download if file already exists (huggingface)](https://github.com/hfg-gmuend/zoomaker/commit/6ae9be38de0ecc2145a9d6c66cf0b9a4ec66c3b0)

- [Add Zoomaker module and fixed various bugs](https://github.com/hfg-gmuend/zoomaker/commit/4f2480d0d69dd09412c087d094f758a2bd8671a2)
- [Add check to skip download if file already exists in Zoomaker](https://github.com/hfg-gmuend/zoomaker/commit/3e5c59b7fc3fa4f5a26a4f04ee5a45ee915c6d1f)
- [Add skipTest for missing cache file in ZoomakerTestCase](https://github.com/hfg-gmuend/zoomaker/commit/05437661511631db6244494457d55f7862226665)
- [Add support for custom YAML file in install and run commands; update README and tests](https://github.com/hfg-gmuend/zoomaker/commit/f2b8eb80121d21a044fe41e5c7918baf4e0c644b)

- fixed failing civitai download
- added optional civitai api key (bearer) per download
- added automatic filename extraction from header
- added option to run individual tests

- Upgraded dependencies huggingface-hub and GitPython
- New feature: existing web downloads are skipped
- Removed obsolete --no-symlinks zoomaker argument
- Updated readme and added Custom Cache Location hint