App sidebar mode and optimizations

[benjaminpkane]

Change log

• Significantly optimizes the performance of the sidebar by lazily computing statistics only for currently visible fields
• Added new sidebar modes all|best|fast with updated default behavior that further optimizes the performance of the App for large datasets
• Added support for configuring the sidebar mode dynamically in the App and programmatically on a per-dataset basis
• Added support for programmatically configuring sidebar groups and default expansion states on a
  per-dataset basis

Issues resolved

• Resolves [BUG] Video out of sync with label overlay #1270
• Resolves [BUG] Cannot hide selected samples  #2255
• Resolves [BUG] Error when navigating away from a grouped dataset in group stats mode #2244

[brimoor]

LGTM