Summary: A lot of Discover's users don't seem to get that the Home page is a list of featured apps. Well, let's tell them!

Test Plan:
Tested in KDE Neon. Before:
{F5647495}

After:
{F5650154}

Reviewers: apol, #discover_software_store

Reviewed By: apol, #discover_software_store

Subscribers: ankits, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D9868