Nimble Table: cell view (custom element) and cell state changes

[msmithNI]

Pull Request

🤨 Rationale

Fixes #997

👩‍💻 Implementation

Implementation is similar to what was outlined in the the HLD (PR):

• Add a TableCellView<TCellRecord, TColumnConfig> class. TableCellView instances will be used in TableCells, instead of the old approach (column-provided cellTemplate and cellStyles).
• Add cellViewTag property to TableColumn (links the column with the associated TableCellView type)
• TableCellView defines a focusedRecycleCallback() method which is a no-op by default. If a cell view contains a focusable element, and a cell is focused, and then a scroll (row recycle) occurs, this gives the cell view an opportunity to commit/blur/etc.
  • We don't yet have a column type exercising this, but there's a new autotest for this code path.
• If a cell action menu is open when a scroll/ row recycle occurs, the action menu is closed (via the associated menu button).

🧪 Testing

• Updated existing autotests
• Added new tests for focusedRecycleCallback and the code that closes action menus on scroll
• Manually tested table in Storybook + Angular + Blazor example apps

✅ Checklist

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