Incorporate color and alignment helpers into context pad

[nikku]

Is your feature request related to a problem? Please describe.

Coloring and alignment utilities are currently only exposed via API and been must be provided to users via custom UI controls.

For the sake of a unified modeling experience it would make sense to make these elements available directly from the modeler user interface.

Describe the solution you'd like

These actions are available through the context pad:

• Alignment and distribution
• Coloring (single and multi element) -> ⚠️ warn web-modeler team after release, since they currently have their own color picker built on top of bpmn-js
  • Design issue: https://github.com/camunda/camunda-modeler-design/issues/101
  • Note: related issue on vs-code-bpmn-io: Support ability to set colors vs-code-bpmn-io#93 (mark as fixed-upstream after color picker feature is completed

Describe alternatives you've considered

Keep it as is.

Additional context

All mentioned tools are multi element, which we do not support in the context pad just yet (bpmn-io/diagram-js#278).

---

Depends on bpmn-io/diagram-js#587
Related PR: #1525

[nikku]

A demo showcasing this end-to-end is available here (link to respective multi-element-context-pad branches in bpmn-js and bpmn-js -> diagram-js.

Demo using the feature end-to-end:

[nikku]

These are now incorporated via different places, available at the core, or dedicated utilities: #1680, https://github.com/bpmn-io/bpmn-js-color-picker.