stream: Frame-align divided audio segments

stream: Frame-align divided audio segments

Executing below command will not produce any audio:

  pacat  --channels=3 /dev/urandom

Turns out that pa_stream_write() breaks large audio buffers into
segments of the maximum memblock size available -- a value which
is not necessarily frame aligned.

Meanwhile the server discards any non-aligned client audio, as a
security measure, due to some earlier reported daemon crashes.
Thus divide sent audio to the expected aligned form.

CommitReference-1: 22827a5e1e62
CommitReference-2: 150ace90f380
BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=98475
BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=77595
Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>