Allow the playbin object from the gstreamer backend to be configured.
Created by: wdehoog
Configurable properties: buffer-size, buffer-duration and flags.
The configuration of these properties can be done in a file: .config/media-hub/media-hub.conf
This allows to try to reduce stuttering of high bitrate media (for example for playing flac audio see https://github.com/ubports/ubuntu-touch/issues/1423).