feat: add subMenuOpenByEvent option to open sub-menus via mouseover

[ghiscoding]

• when first implemented sub-menus, I thought it was complex to add open sub-menus via mouseover (not just click event) but it turns out to be quite easy with the latest code that was put in place for sub-menus. So this PR adds the mouseover option and does make it the default event (we have 2 options: click or mouseover and the latter is the default)
• this new mouseover will be the default but user could change it to work via click event only by changing the option to subMenuOpenByEvent: 'click' (instead of the default which is subMenuOpenByEvent: 'mouseover')

[codecov]

Codecov Report

Merging #1161 (a54db8e) into master (b524ef1) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1161   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          245       245           
  Lines        17147     17166   +19     
  Branches      6186      6196   +10     
=========================================
+ Hits         17147     17166   +19     

Files	Coverage Δ
packages/common/src/extensions/menuBaseClass.ts	100.00% <100.00%> (ø)
...ges/common/src/extensions/menuFromCellBaseClass.ts	100.00% <100.00%> (ø)
packages/common/src/extensions/slickCellMenu.ts	100.00% <ø> (ø)
packages/common/src/extensions/slickContextMenu.ts	100.00% <ø> (ø)
packages/common/src/extensions/slickGridMenu.ts	100.00% <100.00%> (ø)
packages/common/src/extensions/slickHeaderMenu.ts	100.00% <100.00%> (ø)