feat: enhance a11y

[mlmoravek]

Part of #596
Fixes #455
Fixes #446

Proposed Changes

• Add several addional handler for a11y purpose
• Add several tabindex and role properties for a11y
• Change DatepickerMonth & DatepickerTableRow a tag to div
• Fix Steps generic component child item
• Change Steps nav item markup to ol/li
• Small code refactorings

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (796ed9f) 54.25% compared to head (4d4ce5c) 54.25%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #762   +/-   ##
========================================
  Coverage    54.25%   54.25%           
========================================
  Files           32       32           
  Lines         1480     1480           
  Branches       527      527           
========================================
  Hits           803      803           
  Misses         677      677           

Flag	Coverage Δ
oruga-next	54.25% <100.00%> (ø)

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