Add Qt::FontRole data

[Overflwn]

This is related to #35 and just adds the ability to change the Qt::FontRole for a specific logger. It works just like the background and foreground colors.

I also added a "Bold" checkbox to the toolbar which demonstrates this feature. Unit tests are also included in this PR.

Additionally, I made a small change to the style popup, it resets the QLineEdit and QCheckBox values if the std::optionals are std::nullopt.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (670aea5) 97.95% compared to head (3d9e12c) 98.04%.

Files	Patch %	Lines
src/qspdlog_model.cpp	96.15%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #45      +/-   ##
==========================================
+ Coverage   97.95%   98.04%   +0.09%     
==========================================
  Files          10       10              
  Lines         928     1022      +94     
==========================================
+ Hits          909     1002      +93     
- Misses         19       20       +1     

Flag	Coverage Δ
uitests	98.04% <99.00%> (+0.09%)	⬆️

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[arsdever]

Overall, looks great 👍🏼.

Please pass through a clang-format tool after fixing the comments. The formatting seems to be odd.

[arsdever]

With this PR applied, the sample dialog and the resulting log messages look like this

[Overflwn]

@arsdever I applied your suggestions and fixes