Port potd (picture of the day) dataengine to KF5.

Summary:
Osei site was discontinued, replace it with its successor which is also from
NOAA. Also fix flickr, wikipedia, national geography provider, which are
broken becauses of changes from providers. Use KPluginLoader to load plugin
instead of KServiceTypeTrader.

Test Plan: Manually with plasmaengineexplorer

Reviewers: #plasma, mart

Reviewed By: mart

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D3183