Remove tugUtils.getAPiUrl() and integrate lang and entry-point-url attributes

packages/common/test/unit.js

packages/common/tug-utils.js

toolkit-showcase/assets/dbp-toolkit-showcase.html.ejs

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