Audio V4: Move common files before refactor

This will make diff much more clear and allow git to follow the files.

Bug: 38184704
Test: compile
Change-Id: I41ccb41c334aa56d3935be333e6227dd99773766
Signed-off-by: Kevin Rocard <krocard@google.com>
diff --git a/audio/common/all-versions/README b/audio/common/all-versions/README
new file mode 100644
index 0000000..d8df022
--- /dev/null
+++ b/audio/common/all-versions/README
@@ -0,0 +1 @@
+This folder contains code common to all versions of the audio API