Cleanup Parallel Backend

[AnesBenmerzoug]

Description

This PR closes #360 #535 #536 and addresses part of #385

Changes

• Adapted docstrings and code to rely on user to configure joblib and initialize ray with desired parameters.
• Set minimum version of joblib to 1.3.0 in order to support parallel_config context manager.
• Deprecated most fields of ParallelConfig except for backend in preparation for removing it altogether in favour of letting the user instantiate the parallel backend instance and passing it to the method.
• Moved parallelization and caching documentation to separated advanced usage page and expanded it.
• Fixed caching and dask influence calculator docstrings.

Checklist

• Wrote Unit tests (if necessary)
• Updated Documentation (if necessary)
• Updated Changelog
• If notebooks were added/changed, added boilerplate cells are tagged with "tags": ["hide"] or "tags": ["hide-input"]

[mdbenito]

Cool. Simple is always better 👍🏽 I left a few minor comments and a few questions. Maybe we can talk on Monday about how the final usage pattern will look like?

[mdbenito]

Looking good 👍🏽