V3 - Add Custom Attributes for Bulk Actions

[lrljoe]

This PR adds several new methods for customising the look & feel of the Bulk Actions "th" "td" and associated checkboxes, methods documented, but summarised as follows:

• setBulkActionsThAttributes(array $bulkActionsThAttributes)
  You may pass an array to this method, which allows you to pass Custom Attributes into the table header

• setBulkActionsThCheckboxAttributes(array $bulkActionsThCheckboxAttributes)
  You may pass an array to this method, which allows you to pass Custom Attributes into the Select All/None checkbox in the Table Header

• setBulkActionsTdAttributes(array $bulkActionsTdAttributes)
  You may pass an array to this method, which allows you to pass Custom Attributes into the td containing the Bulk Actions Checkbox for a row

• setBulkActionsTdCheckboxAttributes(array $bulkActionsTdCheckboxAttributes)
  You may pass an array to this method, which allows you to pass Custom Attributes into the Bulk Actions Checkbox for the row

### Currently pending test creation.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (db0689d) 88.99% compared to head (b8f623a) 89.07%.
Report is 5 commits behind head on develop.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #1564      +/-   ##
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+ Coverage      88.99%   89.07%   +0.07%     
- Complexity      1268     1276       +8     
=============================================
  Files             96       96              
  Lines           3008     3030      +22     
=============================================
+ Hits            2677     2699      +22     
  Misses           331      331              

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