Add code splitting; Split main and demo bundle

...es/knowledge-base-web-page-element-view/assets/index.html

packages/knowledge-base-web-page-element-view/package.json

...ges/knowledge-base-web-page-element-view/rollup.config.js

packages/knowledge-base-web-page-element-view/src/demo.js

packages/knowledge-base-web-page-element-view/src/index.js

...view/src/vpu-knowledge-base-web-page-element-view-demo.js

...ment-view/src/vpu-knowledge-base-web-page-element-view.js

packages/knowledge-base-web-page-element-view/test/unit.js