[FEAT] Implement the first iteration of the "Predictions demo"

[tbouffard]

This issue is the container for all issues of the first iteration. BPMN Diagram: Pizza diagram from the examples provided by the BPMN specification.

We will provide 2 use cases

• predicted late: vendor “Bake the pizza” in progress (started for 45 min for instance). Customer: predicted next task will be “Ask for pizza” after the complex gateway
• predicted on time: vendor “Deliver pizza” in progress. Customer, predicted "received pizza" (we will highlight the whole path/branch)
• Design: we use the same design as for the monitoring demo for legends, panels and tabs

We will work on the master branch. The demo will be publicly available in the live environment when the first iteration is completed.

• [x] #261
• [x] Improve the Pizza diagram for a better rendering.
  • 1st attempt in #264
  • 2nd attempt in #266
• [x] #263
• [x] Highlight running elements #265
• [x] Highlight next predicted elements #275
• [ ] Add popup/popover on "running elements". Display at least information about the start date. Content to be discussed prior starting the implementation
  • do we let user perform actions with button inside the popover? not for now
  • we can use tippy.js as we do in custom behavior example
• [ ] On predicted paths highlight: make non predicted path less visible
• [ ] Restore message flow icons in the BPMN diagram once
  • bug in bpmn-visualization is fixed: https://github.com/process-analytics/bpmn-visualization-js/issues/1622
  • being able to style message flow icon precisely: https://github.com/process-analytics/bpmn-visualization-js/issues/928
• [ ] Review CSS to use rem instead of em or px (may be use in the 'pulse' animation)
• [ ] Add legends
• [ ] Add controls?
• [ ] Display the demo in the HTML home page for a public access