[dask] Preparing bob.bio.base for dask pipelines

THIS IS A WIP

Working out how bob.bio.base should be with dask pipelines. Some things to be done in the MR is.

• Remove all traces of verify.py. Pipelines needs to be defined with dask. This includes the removal of: FileSelector, Grid configurations, ./script/grid_search, ./script/enroll, ./script/extract, ./script/preprocess, ./baselines
• Move the biometrics pipeline from bob.pipelines to here
• Document the package on: 1-) How to use the resources available (databases, algorithms, preprocessors, etc..), 2-) How to create new databases, 3-) How to create new pipelines (this should be in bob.pipelines)
• Rethink the file list interface
• Review which dependencies to keep. For instance, bob.learn.linear, bob.learn.em, bob.learn.activation, bob.math (consider use scikit-learn).
• Implement missing pipelines (for instance, score normalization/calibration pipeline)
• Database paths patched in ~/.bobrc
• Redesign the resource.py as CLI commands