Add a settings menu (offline)

[GuillaumeFavelier]

In order to provide a settings menu:

1. rcParams should be refactored heavily to allow default values sharing
2. params should be loaded from a JSON file or dumped to a default location
3. A setting interface should modify and update the JSON file

Closes #15

[codecov]

Codecov Report

Merging #45 into master will increase coverage by 0.34%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #45      +/-   ##
==========================================
+ Coverage   99.10%   99.45%   +0.34%     
==========================================
  Files          13       14       +1     
  Lines         897     1100     +203     
  Branches      108      129      +21     
==========================================
+ Hits          889     1094     +205     
  Misses          3        3              
+ Partials        5        3       -2     

Impacted Files	Coverage Δ
blockbuilder/app/start.py	73.33% <100.00%> (+1.90%)	⬆️
blockbuilder/block.py	100.00% <100.00%> (ø)
blockbuilder/core_plotter.py	100.00% <100.00%> (ø)
blockbuilder/element.py	100.00% <100.00%> (ø)
blockbuilder/grid.py	100.00% <100.00%> (ø)
blockbuilder/interactive_plotter.py	100.00% <100.00%> (ø)
blockbuilder/main_plotter.py	99.40% <100.00%> (+0.60%)	⬆️
blockbuilder/params.py	100.00% <100.00%> (ø)
blockbuilder/plane.py	100.00% <100.00%> (ø)
blockbuilder/selector.py	100.00% <100.00%> (ø)
... and 3 more

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[GuillaumeFavelier]

For now all the code of SettingDialog is on __init__, this need to be refactored and improved.

[GuillaumeFavelier]

ToDo:

• QMessageBox for Apply and Cancel buttons
• QColorDialog for color selection
• Bug with the setting layout on Windows
• Bug when importing a blockset with different dimensions