Wrapping Hilbert transform

[wulfdewolf]

This PR introduces a new signal module, which contains functions for extracting envelopes and phases (using Hilbert transform).
Most of the functions are wrappers around scipy.signal.hilbert:

• apply_hilbert_transform
• compute_hilbert_envelope
• compute_hilbert_phase

Also moved detect_oscillatory_events to this module, since it is a better fit than filtering.

In the future we will add a function to this module that uses something like find_peaks and then interpolation to extract phases, see #584.

Documentation

The new functions have detailed docstring examples.
A new user-guide was added for this module specifically, it focuses on extracting phases/envelopes.
Places that used the Hilbert transform that now use this module:

• the filtering tutorial where spike phases are extracted
• the ripple detection module that is in the making

Testing

Tests have been added for:

• input/output checks
• output versus scipy.

Related issues

Addresess #568.

[codecov]

Codecov Report

❌ Patch coverage is 90.00000% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
pynapple/process/signal.py	89.47%	4 Missing and 2 partials ⚠️

Files with missing lines	Coverage Δ
pynapple/core/time_series.py	93.22% <100.00%> (ø)
pynapple/process/__init__.py	100.00% <100.00%> (ø)
pynapple/process/filtering.py	94.54% <ø> (+2.70%)	⬆️
pynapple/process/signal.py	89.47% <89.47%> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.