Make 'example.odt', 'license.txt' and 'notice.txt'
(which can be opened via the "About" dialog)
resources of the app by copying them to a new directory
'res_generated' instead of into assets, and include
'res_generated' into resources, then use an
'android.resource://' URI instead of a 'file:///assets/'
one in AboutDialogFragment.
The latter does not work with when passed as a parameter
to 'ContentResolver.openInputStream'.
Adapt/Simplify 'LibreOfficeMainActivity#copyFileToTemp' to
make loading those docs using the 'android.resource://'
URI work and use the existing 'copyStream' method for copying from
the input to the output stream.
This is in preparation for upcoming commit with Change-Id
I7731ef81a4242fa0ce3b3fd8ced1683a6a6bee8c,
"android: Always create a temporary local copy of the doc".
Change-Id: I7731ef81a4242fa0ce3b3fd8ced1683a6a6bee8c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/113881
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>