Speed up import time

[hoxbro]

The main focus is to get the import time down. Done with python -X importtime -c "import holoviews" 2> log.txt && tuna log.txt

For now, I have moved IPython, Ibis, and Panel to be lazy imports.

Current main (taking 1.256 seconds to load):

With this PR (takes 0.338 seconds to load):

[codecov-commenter]

Codecov Report

Merging #5719 (ad2575b) into main (f4c4c12) will increase coverage by 0.00%.
The diff coverage is 92.85%.

@@           Coverage Diff           @@
##             main    #5719   +/-   ##
=======================================
  Coverage   88.24%   88.24%           
=======================================
  Files         304      305    +1     
  Lines       62680    62693   +13     
=======================================
+ Hits        55309    55324   +15     
+ Misses       7371     7369    -2     

Impacted Files	Coverage Δ
holoviews/__init__.py	70.49% <66.66%> (+2.69%)	⬆️
holoviews/core/data/ibis.py	81.56% <94.44%> (+0.80%)	⬆️
holoviews/ipython/__init__.py	75.92% <100.00%> (+0.30%)	⬆️
holoviews/tests/util/test_init.py	100.00% <100.00%> (ø)
holoviews/util/__init__.py	74.68% <100.00%> (ø)

... and 1 file with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[philippjfr]

Only question from my side is why you had to make IPython imports lazy in holoviews.ipython if you already made the holoviews.ipython import dependent on whether IPython is in sys.modules.

[hoxbro]

Good catch. I think I made those changes before I added the sys.module change. I have reverted it now.

[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.