tests : model metadata loading from huggingface (#19796)
* Add model metadata loading from huggingface for use with other tests
* Add incremental chunking instead of full redownload, fix caching issue and add warning when it fails
* Add support for split models, load metadata from each individual split file, also avoid mmproj
* Code cleanup, revert incremental downloading
* Only compile when cpp-httplib has SSL support
* Fix formatting
