Comment 2 for bug 1730752

Force-pushed a squashed commit back to the same branch with a few additional changes.

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Adds a new "Manage Columns" grid action which opens a batch grid column configuration dialog. In the dialog, users can show/hide multiple columns at once. The column position actions (left/right/far-left/far-right) and sort priority settings have also been moved to this new UI.

The existing 'Configure Columns' action has been renamed to 'Managed Column Widths' and now only supports making columns wider and narrower.