feat: add bpmn-js-color-picker dep

[tpucci]

Closes #93

• chore: add bpmn-js-color-picker dep
• feat: add bpmn-js-color-picker to the pad

[CLAassistant]

All committers have signed the CLA.

[tpucci]

I have one issue left, color icons are not displayed by the webview. We need to change them for SVG html tags.

Should I open a PR on bpmn-js-color-picker repo ?

EDIT

The bug cause was actually Refused to load the image '<URL>' because it violates the following Content Security Policy directive: "img-src 'self' <URL> blob:".. Fixed it, see below.

[tpucci]

Ok, I made it work adding a Content-Security-Policy.

  <meta http-equiv="Content-Security-Policy"
  content="default-src 'none';
  font-src 'self' data:;
+ img-src 'self' data:;
  img-src ${webview.cspSource} blob:;
  style-src ${webview.cspSource};
  script-src 'nonce-${nonce}';">

[smbea]

@philippfromme added you as a reviewer since you were weighting in on the issue

[nikku]

I think this is a fine addition to the editor. Thank you.

[nikku]

This will be released with the upcoming v0.19.0 release. 🎉