DeMask, inference CLI, lightning 0.9.0 and beautfil docs !

Highlights

• Refactored base models to ease publishing and loading
• Improve Asteroid extensibility (without -e install) with register/get logic.
• asteroid-infer CLI for easy enhancement/separation
• DeMask recipe + pretrained model
• Upgrade to lightning 0.8.1+
• Brand new docs ! (thanks @michelolzam)
• Brand new landing page ! (thanks @michelolzam)

Changelog

Added

• [hub] Add DeMask to hubconf (#242)
• [models] Add 16k popcornell/DPRNNTasNet_WHAM_enhancesingle enhancement
• [src & egs] Add DeMask: Surgical mask speech enhancement recipes (#235)
• [models] Add pretrained DeMask name to URL mapping
• [src & egs] PyTorchLightning upgrade to 0.9.0 (stable from 0.8.1 on) (#217)
• [CLI] Add asteroid-infer CLI to enhance/separate from the command line (#236)
• [docs] New docs theme ! (#230)
• [tests] Improve tests for new model interface (#234)
• [docs] Add license info to FUSS Dataset
• [src] Cleaner try/except/else in base_models.py (thanks @jonashaag)
• [src] Add LibriMix.loaders_from_mini in librimix_dataset.py (#229)
• [src] Add register command to gettable modules (#231)
• [models] Add groadabike's pretrained model's URL (#228)
• [src] Import MultiScale spectral loss in init.py
• [docs] Include new notebook: follow up of #221 (#226)
• [src] Add LambdaOverlapAdd usage example (#221)

Changed

• [src] Improve BaseModel.separate (#236 follow up) (#238)
• [hub] Remove args in hub models, don't accept positional args after kwargs
• [src] Refactor BaseTasnNet in two: better loadable/serializable models (#232)

Fixed

• [CLI] Fix large output volume in asteroid-infer
• [docs] Fix theme installation, grunt build and import errors in docs (#240)
• [tests] Fix wrong separate method in model tests (#241)
• [src] Recipe name in publisher + dataset name fix (#239)