On some systems, the SDL audio callback is not called frequently enough
(for example it requests 5ms of samples every 10ms), because the output
buffer is too small.
By default, we want to use a small value (5ms) to minimize latency and
buffer underrun, but if it does not work well, users need a way to
increase it.
Refs #3793 <https://github.com/Genymobile/scrcpy/issues/3793>
The README.md page is HUGE. Split it up.
Also document audio forwarding and improve installation instructions for
each platform and user documentation.
PR #3774 <https://github.com/Genymobile/scrcpy/pull/3774>
