APK Creation instructions need update

The instructions here: https://gitlab.com/SteveWyshy/activist-apprentice-course-template/blob/master/content/6-publishing-a-course/1-build-apk.md are pretty close to the final version as documented here: contentascode/activist-apprentice#19 (closed)

Mostly it looks like the latter half needs to be updated. ALSO update required memory to 8gb from the current 4gb