Remove enclosing provider

src/dbp-signature.js

 import {AppShell} from '@dbp-toolkit/app-shell';
 import * as commonUtils from '@dbp-toolkit/common/utils';
-import {Provider} from '@dbp-toolkit/provider';
 
-// It's important that the Provider is created before the AppShell, so the AppShell can subscribe to the Provider
-commonUtils.defineCustomElement('dbp-provider', Provider);
 commonUtils.defineCustomElement('dbp-signature', AppShell);