[Bars] Support additional click and tooltip use cases / examples (especially grouped/stacked)

[techniq]

• Individual bar tooltips
  • Ability to mouse over specific bar segment of a stacked and/or grouped bar
  • Likely just an example using <Chart tooltip={{ mode: 'manual' }}> with explicitly rendered <Bar tooltip> (add support)
• Individual bar on:click
  • Ability to click on specific bar segment of a stacked and/or grouped bar
  • Likely just an example with explicitly rendered <Bar on:click={...}> (add support)