Create embedding example

[nikku]

Proposed Changes

This adds an embedding example based off the previous work by @jarekdanielak:

What this example does:

• Shows how different BPMN diagrams embed nicely within a larger website
• Work friendly (enough) with each other
• Shows there is work for us to do (i.e. "auto-focus" breaks with the site interaction)

Checklist

To ensure you provided everything we need to look at your PR:

• Brief textual description of the changes present
• Visual demo attached
• Steps to try out present, i.e. using the @bpmn-io/sr tool
• Related issue linked via Closes {LINK_TO_ISSUE} or Related to {LINK_TO_ISSUE}

[nikku]

This is accompained by bpmn-io/diagram-js#956.

Checkout how the interaction improves with an explicit canvas focus and a native focus integration of navigation/* modules:

npx @bpmn-io/sr bpmn-io/bpmn-js-examples#keyboard -l bpmn-io/diagram-js#optional-autofocus -c 'npm start -w embedding'

[barmac]

This is so great! This is a great case for the diagram-js change.

I was wondering whether we should have "escape to blur". This does not work in Web input elements, but works for the address bar. I guess we will stick to the Web platform behavior.

[nikku]

Do you consider bpmn-io/diagram-js#956 along with this change? I.e. did you try the before and after behavior?

[barmac]

Yes, I tried both and with the proposed change it works better to me.