v14.0.0-beta.6

What's Changed

• feat: Add scrollbar buttons using buttons options, closes #465.
• refactor: Reuse similar code in track, thumb and buttons directives.
• refactor: content wrapper selector should be direct child of the viewport.
• refactor: Use swithcMap instead of expand for track long ongoing pointer down event.
• refactor: Only use getRtlScrollAxisType once on initialization in SmoothScrollManager.
• refactor: matSelectViewport use instant scroll function to scroll to the selected item in the list.
• refactor: Use getBoundingClientRect in all directives instead of clientWidth and clientHeight for high precision calculation.

Full Changelog: v14.0.0-beta.5...v14.0.0-beta.6