[FIX] Orange can be imported without Qt (fixed importing localization)

[janezd]

Issue

Fixes #6952. Requires biolab/orange-canvas-core#320 to be merged and released.

Description of changes

Import localization from a place that doesn't require Qt.

The most important change is the one in configuration of Trubar - this will allow running Orange without Qt.

The other two changes in [Orange/widgets/utils/localization/__init__.py](https://github.com/biolab/orange3/compare/master...janezd:fix-headless-orange?expand=1#diff-3bf6fd4d089b6924794714d11768d90dbac35b1b370e9cfc788c6cd6f216eece) are not strictly necessary, but prevent a warning about importing localization from a deprecated module.

Includes

• Code changes
• Tests
• Documentation

[markotoplak]

I tested these two PR (installed, so translated, at first I forgot about this) and they did fix the reported issue for me .

But then, when testing, if I only remove pyqt* in my environment, I still get complains from Orange's __init__.py:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/marko/dev/orange3/Orange/__init__.py", line 30, in <module>
    from AnyQt.QtCore import QObject
  File "/home/marko/venv312/lib/python3.12/site-packages/AnyQt/QtCore.py", line 274, in <module>
    from PyQt5.QtCore import *
ModuleNotFoundError: No module named 'PyQt5.QtCore'

I also had to remove AnyQt for them to disappear. Did you have to do that too?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.47%. Comparing base (c2c1648) to head (74f8282).
Report is 97 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6955      +/-   ##
==========================================
+ Coverage   88.45%   88.47%   +0.01%     
==========================================
  Files         331      332       +1     
  Lines       73099    73277     +178     
==========================================
+ Hits        64659    64831     +172     
- Misses       8440     8446       +6     

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