Add help menu and program version info

[mfl28]

• Adds Help menubar item with sub-menus that link to the documentation and open an about dialog.
• Adds the program version to the app window title.
• Updates and extends unit tests.

Closes #58 .

[codecov]

Codecov Report

Patch coverage: 90.00% and no project coverage change.

Comparison is base (cc1e2ff) 85.74% compared to head (e08d9c2) 85.75%.

Additional details and impacted files

@@            Coverage Diff            @@
##             master      #59   +/-   ##
=========================================
  Coverage     85.74%   85.75%           
- Complexity     1404     1409    +5     
=========================================
  Files            92       92           
  Lines          5745     5763   +18     
  Branches        521      522    +1     
=========================================
+ Hits           4926     4942   +16     
- Misses          560      562    +2     
  Partials        259      259           

Impacted Files	Coverage Δ
.../mfl28/boundingboxeditor/BoundingBoxEditorApp.java	0.00% <0.00%> (ø)
...mfl28/boundingboxeditor/controller/Controller.java	77.84% <77.77%> (-0.12%)	⬇️
...om/github/mfl28/boundingboxeditor/ui/MainView.java	83.26% <100.00%> (+0.20%)	⬆️
...github/mfl28/boundingboxeditor/ui/MenuBarView.java	100.00% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

88.5% Coverage
0.0% Duplication