use verbosity and options in meson.build similar to gstreamer_example

[maureeungaro]

verbosities = ['-verbosity.plugins=2',
'-verbosity.gdigitization=2',
'-verbosity.gtouchable=2',
'-verbosity.gstreamer=2',
'-debug.plugins=true',
'-debug.gtouchable=true',
'-debug.gstreamer=true',
]
root = ['-gstreamer="[{format: root, filename: out}]"']
ascii =[ '-gstreamer="[{format: ascii, filename: out}]"']
buffer = ['-ebuffer=20']