Add QgisBot to make it easier to access utility functions

[Joonalai]

This PR:

• Adds QgisBot as qgis_bot and module_qgis_bot fixtures.
• Adds utility method QgisBot.create_feature_with_attribute_dialog to create features safely with default values. This makes creating features closer to what it really is using GUI.
• Moves get_qgs_attribute_dialog_widgets_by_name to be part of QgisBot

[codecov-commenter]

Codecov Report

Merging #17 (07f8e97) into main (0000726) will increase coverage by 0.17%. The diff coverage is 60.00%.

@@            Coverage Diff             @@
##             main      #17      +/-   ##
==========================================
+ Coverage   53.28%   53.46%   +0.17%     
==========================================
  Files           6        7       +1     
  Lines         426      462      +36     
==========================================
+ Hits          227      247      +20     
- Misses        199      215      +16     

Flag	Coverage Δ
pytest	53.46% <60.00%> (+0.17%)	:arrow_up:

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Impacted Files	Coverage Δ
src/pytest_qgis/utils.py	75.00% <0.00%> (-0.30%)	:arrow_down:
src/pytest_qgis/pytest_qgis.py	52.30% <28.57%> (-0.72%)	:arrow_down:
src/pytest_qgis/qgis_bot.py	66.66% <66.66%> (ø)

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