Implement Flexbox Grid Formatting to Default Item Tile Listing Widget (#11345)

The default layout of the Items_TileListing widget has been updated to utilize a Flexbox structure rather than Bootstrap. This change handles presentation of the results in the following ways:

autoScrollTopOnTileLoad Option in Items_TileListing Widget (#11361)

 

The widget option autoScrollTopOnTileLoad will force the browser to scroll to the top of the page whenever the tile listing is reloaded by either paging or filtering when the pagingMode is set to "paged". The default value is true. The option has no impact when pagingMode is set to "endless". 

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