Experimental hf logger (#1456)
* first draft for an hflogger
* move to huggingface_hub
* copyright
* Add default tensorboard logger
* leverage to push to hub in the background
* Push ot hub on context manager closing
* remove clunky HFLoggerMixin and focus on tensorboard
* mark HFSummaryWriter as experimental
* automatic push in HFSummaryWriter
* simplify logic if only 1 LFS file
* more verbose
* Append logdir to path_in_repo
* add apckage reference
* fix typing
* fix kwargs in doc
* fix type
