[FEAT] List the sites that reference bpmn-visualization

[tbouffard]

Is your feature request related to a problem? Please describe.
bpmn-visualization is mentioned on various sites and we should advertise about this on the website.

Describe the solution you'd like
Create a dedicated page or section on the home page to list the sites that reference bpmn-visualization:

• "BPMN in Color": https://github.com/bpmn-miwg/bpmn-in-color/blob/master/README.md#implementers
• bpmnmatrix: https://bpmnmatrix.github.io/
• miwg-test-suite: in progress bpmn-miwg/bpmn-miwg-test-suite#896

Briefly explain what the sites provides, why we are referenced, ....