Add content to the news markdown page and update other pages
While merging faidare into data-discovery, we found that there was no markdown page for the /news
page.
MR !371 added empty pages to avoid runtime errors, but the page should be filled with relevant content (as we discussed in the last meeting in July).
The other pages are present and with content, but some content might need to be updated before going to production (for example the Help section details how the various tabs works, and they are not the same in the merged version of faidare).