Create pulseaudio upstart job, and add default client configurations + startup volume.

src/platform/audioconfig/pulse/firstrun.pa

Index: src/platform/audioconfig/pulse/firstrun.pa
diff --git a/src/platform/audioconfig/pulse/firstrun.pa b/src/platform/audioconfig/pulse/firstrun.pa
new file mode 100644
index 0000000000000000000000000000000000000000..8d330f02f6d8f09ee5913124ccba3a09c6c4cc09
--- /dev/null
+++ b/src/platform/audioconfig/pulse/firstrun.pa
@@ -0,0 +1,16 @@
+#!/usr/bin/pulseaudio -nF
+
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# A PulseAudio script that sets the initial volume of the first sink to 70%
+# of PA_NORM (generally 70% of max volume).
+#
+# TODO(ajwong): There should be one file per board that configures all
+# devices, not just the first.
+
+.nofail
+
+set-sink-mute 0 false
+set-sink-volume 0 45876