[ENH] Remove use of pkg_resources

[ales-erjavec]

Issue

pkg_resources is deprecated.

Requires biolab/orange-canvas-core#289

Description of changes

Remove/replace use of pkg_resources with importlib.metadata, importlib.resources, pkgutil and packaging.

Includes

• Code changes
• Tests
• Documentation

[codecov-commenter]

Codecov Report

Attention: 6 lines in your changes are missing coverage. Please review.

Comparison is base (cc4feec) 71.65% compared to head (9b5ed7b) 71.72%.

Files	Patch %	Lines
orangewidget/workflow/errorreporting.py	0.00%	3 Missing ⚠️
orangewidget/workflow/config.py	33.33%	2 Missing ⚠️
orangewidget/workflow/discovery.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #260      +/-   ##
==========================================
+ Coverage   71.65%   71.72%   +0.07%     
==========================================
  Files          34       34              
  Lines        9091     9086       -5     
==========================================
+ Hits         6514     6517       +3     
+ Misses       2577     2569       -8     

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[PrimozGodec]

After I check out this PR, and run orange-canvas --force-discovery, I get the following error:

Traceback (most recent call last):
  File "/Users/primoz/python-projects/orange-canvas-core/orangecanvas/registry/discovery.py", line 231, in process_loader
    callable(self)
  File "/Users/primoz/python-projects/orange3/Orange/widgets/__init__.py", line 45, in widget_discovery
    discovery.process_category_package(pkg, distribution=dist)
  File "/Users/primoz/python-projects/orange-canvas-core/orangecanvas/registry/discovery.py", line 213, in process_category_package
    cat_desc.project_name = distribution.name
  File "/Users/primoz/miniconda3/envs/orange3/lib/python3.9/site-packages/pkg_resources/__init__.py", line 2903, in __getattr__
    return getattr(self._provider, attr)
AttributeError: 'PathMetadata' object has no attribute 'name'

Am I doing anything wrong? I also have checked out the newest master version from orange-canvas-core.

[ales-erjavec]

Are you using/testing with biolab/orange3#6655 ?

[PrimozGodec]

Thanks, @ales-erjavec it works with biolab/orange3#6655