Change instances of audio properties 'device' to 'output_device',
and instances of audio properties 'capture_device' to 'input_device',
as well as their subsequent getter & setter functions.
Update the docs to reflect these changes, as well as the
3-to-4 converter for GDScript and CSharp to make proper
conversions (only exception is 'device' since that name
is too vague and might replace non-AudioServer related
instances, such as user comments and variables).
This does not change internal references to references like
'Render Client' and 'Capture Client' in WASAPI; such is outside the
scope of this commit. This also does not change ALSA's references,
considering that it uses 'device' to mean input and output
interchangeably.
Other references are changed, however where applicable,
to be consistent with the new AudioServer methods and property
names.
5300daaff2