Cache jit

[BalzaniEdoardo]

Increased import speed by:

• caching numba jitted functions
• run-time import of pynwb

[codecov]

Codecov Report

Attention: Patch coverage is 46.42857% with 15 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
pynapple/io/loader.py	21.42%	11 Missing ⚠️
pynapple/io/misc.py	20.00%	4 Missing ⚠️

Files with missing lines	Coverage Δ
pynapple/io/interface_nwb.py	79.25% <100.00%> (+0.45%)	⬆️
pynapple/process/_process_functions.py	22.13% <100.00%> (ø)
pynapple/process/correlograms.py	75.57% <100.00%> (ø)
pynapple/io/misc.py	44.95% <20.00%> (-0.92%)	⬇️
pynapple/io/loader.py	52.89% <21.42%> (-1.81%)	⬇️

... and 1 file with indirect coverage changes