1. app.component.ts: Removed deprecated RootMenuItem and used MenuItem instead.
2. criteria.component.ts: Import OpenaireEntities and set variable openaireEntities.
3. criteria.component.html: [Bug fix] Use openaireEntities in no filters message.
4. searchAll.component.ts: [Bug fix] In method "getDefaultEntityToShow()", return "datasources" instead of "content providers".
5. add-content-providers.component.ts: [Bug fix] In error messages use "data sources" wording instead of "content providers".
6. manage-zenodo-communities.component.html: [Bug fix] In <no-load-paging>, set type to "Zenodo communities".