Adapt examples with minor issues to Android

Some examples are good to showcase Qt for Android, but they have issues with a bad layout, or some are not written with mobile usability in mind. Going through the list of examples and fixing their issues to properly work on Android can benefit us in two ways:

• Increase the number of supported examples on Android
• Find bugs or missing features on Android, this includes build issues, layout correct, missing permissions, etc.

The examples' tutorials should be updated accordingly.

UPDATE:

**Since QTBUG-81717 which allows the automatic request of storage permissions is unresolved, the supported Android examples were modified to request storage permissions instead.