Add basic Android support

Summary:
makes it possible to build kookbooktouch for Android. discount needs a few hacks to be built on the binary factory, but it's possible (https://invent.kde.org/sysadmin/ci-tooling/merge_requests/38).

Still needs a few tweaks, e.g. icons are missing, but all fixable

Reviewers: svuorela

Reviewed By: svuorela

Differential Revision: https://phabricator.kde.org/D26315