Patch to add settings for automatic copying to clipboard (android only)

[Ayal.Org]

Hi,

I attach a patch for adding a preference setting to control automatic
copying to clipboard of the code. The patch is Android only -- Sorry I have
no knowledge or access to iOS development.

Basically adds a standard android settings activity with a single
preference, and does not copy to clipboard if not set. The default is to
copy, which is in-line with current behavior.

I attach the git patch, let me know if the format it OK

Thanks for FreeOTP,
Shai