Refactor demo to toolkit showcase

toolkit-showcase/assets/person-select.metadata.json

toolkit-showcase/assets/qr-code-scanner.metadata.json

toolkit-showcase/assets/silent-check-sso.html

toolkit-showcase/package.json

toolkit-showcase/rollup.config.js

...t-showcase/src/dbp-check-in-place-select-demo-activity.js

toolkit-showcase/src/dbp-common-demo-activity.js

toolkit-showcase/src/dbp-data-table-view-demo-activity.js

toolkit-showcase/src/dbp-demo-template.js

toolkit-showcase/src/dbp-file-handling-demo-activity.js

...dbp-knowledge-base-web-page-element-view-demo-activity.js

toolkit-showcase/src/dbp-language-select-demo-activity.js

toolkit-showcase/src/dbp-matomo-demo-activity.js

toolkit-showcase/src/dbp-notification-demo-activity.js

toolkit-showcase/src/dbp-person-profile-demo-activity.js

toolkit-showcase/src/dbp-person-select-demo-activity.js

toolkit-showcase/src/dbp-qr-code-scanner-demo-activity.js

toolkit-showcase/src/dbp-toolkit-showcase.js

toolkit-showcase/src/styles.js

toolkit-showcase/yarn.lock