Make drawing mode selection toggles more compact

[mfl28]

• Makes drawing-mode selection toggle box more compact - removes text descriptions. Improves visual appearance.
• Sets more logical keyboard shortcuts for drawing-mode selection: Ctrl+1/2/3.
• Updates unit tests.

Closes #79 .

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.03 🎉

Comparison is base (6f8a666) 86.07% compared to head (07e88af) 86.10%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master      #80      +/-   ##
============================================
+ Coverage     86.07%   86.10%   +0.03%     
  Complexity     1425     1425              
============================================
  Files            92       92              
  Lines          5787     5788       +1     
  Branches        524      524              
============================================
+ Hits           4981     4984       +3     
+ Misses          546      545       -1     
+ Partials        260      259       -1     

Impacted Files	Coverage Δ
...mfl28/boundingboxeditor/controller/Controller.java	78.45% <ø> (ø)
.../mfl28/boundingboxeditor/ui/EditorToolBarView.java	90.51% <100.00%> (+0.06%)	⬆️

... and 1 file with indirect coverage changes

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[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

100.0% Coverage
0.0% Duplication