feat(style): add Sort icon hint on hover when column is sortable

[ghiscoding]

• we now show a hint while hovering the column. It helps identify if the hovering column is sortable or not, if user doesn't want this behavior he can simply change the SASS variable to opacity of 0.

[codecov]

Codecov Report

Merging #435 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #435   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          141       141           
  Lines         8899      8899           
  Branches      2948      2948           
=========================================
  Hits          8899      8899           

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