Allow icon column to be configured as fixed width

[mollykreis]

Pull Request

🤨 Rationale

This change is part of #1873 and follows the decisions made in #1992

This change adds the ability to configure the width-mode of the icon column. When set to iconSize, the column is a fixed width of 32px, cannot be resized, and hides its sorting & grouping indicators in the header.

👩‍💻 Implementation

There were a number of changes that needed to be made within nimble to facilitate this change.

1. Column Internals
   • Add boolean properties of resizingDisabled and hideHeaderIndicators
2. Table Update Tracker
   • Mark columnWidths as being changed when resizingDisabled changes in columnInternals
3. Table Layout Manager
   • Update to deal with columns that have resizingDisabled === true
4. Table
   • Add logic to hide column dividers that can never be dragged to the left or to the right. This is accomplished by adding a draggable class to the dividers that can be dragged and making the presence of that class a condition in the CSS for showing the divider.
   • Add logic to set indicators-hidden on table columns where hideHeaderIndicators === true
5. Table Header
   • Add a boolean attribute of indicators-hidden that, when true, hides the sorting & grouping indicators in the column header.
6. Icon Column
   • Add width-mode attribute. When the attribute is changed, columnInternals is updated with appropriate values for resizingDisabled, hideHeaderIndicators, minPixelWidth, and pixelWidth.

🧪 Testing

Manually tested in storybook
Updated & added unit tests

✅ Checklist

• I have updated the project documentation to reflect my changes or determined no changes are needed.

[mollykreis]

@atmgrifter00, will you buddy this PR for me?

[mollykreis]

@atmgrifter00, can you re-buddy this PR for me now that there has been a significant change in the direction of the feature?