Added install-ffmpeg-android script for the android cross-compile
Removed android stuff from install-ffmpeg
Changed the yaml variables to include the target arch
Added the arm64 target arch
Task-number: QTQAINFRA-5476
Pick-to: 6.5
Change-Id: Id9609ed0427f2fc42f7f27e7787a81ad145f59be
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>
Reviewed-by: Rami Potinkara <rami.potinkara@qt.io>
Reviewed-by: Lars Knoll <lars@knoll.priv.no>
