[test_utils] Do not re-download ATNT database

Closes #127

See merge request !218

[click][VanillaBiometrics] Fixed click options

Closes #148

See merge request !216

if the data is already inside the low-level db package.
Fixes #127

Optimize scoring if `allow_scoring_with_all_biometric_references == False`

See merge request !214

[VanillaBiometrics] Make some dask arguments visible in the CLI commands

See merge request !213

[legacy databases] delay loading of annotations

See merge request !211

[sphinx] Polished documentation

[py] Fixed rebasing

Improvements on CheckpointWrapper

See merge request !212

[annotators][FailSafe] improvements

See merge request !210

Putting annotator back to the documentation

See merge request !209

Fixing sphinx warnings

See merge request !208

Fixed [typo]

See merge request !207

Created decorators

See merge request !206

[black]

Fix annotators kwargs

See merge request !205

Dask annotators

See merge request !202

Remove stackable preprocessors and extractors

See merge request !204

Now that we have standardized on scikit-learn transformers,
scikit-learn alternatives such as FunctionTransformer, Pipeline,
and FeatureUnion should be used