Datahub: show the correct amount of records on the news page

[jahow]

A new getMatchesCount operation was added to the records repository, and this is used to show the total amount of records.

Before that we used to do a search() with a result amount of 0 to get the results count, but having a separate operation makes sense IMO since it allows finer performance tuning. A later optimization might be to not return the total results count with all search queries, so that track_total_hits is not used all the time for nothing.

Followup of #458

Fixes #627

[github-actions]

Affected libs: api-repository, feature-catalog, feature-record, feature-router, feature-search, feature-map, feature-dataviz, feature-auth, common-domain, api-metadata-converter, feature-editor, ui-search, common-fixtures, ui-elements, ui-catalog, util-shared, ui-widgets, ui-inputs, ui-map, ui-dataviz,
Affected apps: metadata-editor, datahub, demo, webcomponents, search, map-viewer, datafeeder, metadata-converter, data-platform,

• 🚀 Build and deploy storybook and demo on GitHub Pages
• 📦 Build and push affected docker images

[coveralls]

coverage: 83.369% (-2.6%) from 85.964% when pulling daf93f1 on fix-10k-records-limit into 646215e on main.

[fgravin]

👍