Chia

Fixes:
* EpochRunner: Fixed wrong number of validation examples and result_dict possibly not initialized
* extrapolators: Fix extrapolators sometimes reducing precision

Changes:
* test_extrapolators: Test actual output instead of just running experiments
* Factory: Allow instantiation by class name only
* Treat held-out test sets and validation sets separately
* docs: Added JSONDataset documentation
* test_epoch_runner_load_save: Test all combinations of held-out test and validation sets
* keras_idk_hc: Adapt CHILLAX terminology
* Fixed NLTK version because 3.6.6 renames omw corpus to omw-1.4

Changes:
* Updated documentation to include descriptions of architecture and configuration mechanism
* Moved repository to cabrust/chia

Fixes:
* 58 Fixed wrong version of keras installed by setup.py
* 59 Fixed double instantation of KerasFeatureExtractor

Changes:
* Updated TensorFlow version to v2.6

Fixes:
* ExperimentContainer: Fixed not calling dataset setup if config key is missing

Enhancements:
* Added methods from the CHILLAX project to unify code base.

Fixes:
* Bumped TensorFlow and TensorFlow Addons versions to include mitigations against vulnerabilities.

Fixes:
* keras_labelsharing: Fixed hardcoded kappa value

Changes:
* experiment: Initialize dataset setup from configuration dict if possible
* relation: Added reset method