audio policy: add open and active count for IO profiles

Remove the hardcoded limit of one open output stream per IO profile
and add a max open count per IO profile.
Same thing for maximum number of active input streams per IO profile.

Now both the maximum number of opened streams and active streams for
a given profile is stored in that profile.

For now only defaults are set corresponding to legacy behavior,
but these values will be loaded form the audio policy configuration file.

Test: AudioTrack and AudioRecord CTS tests

Change-Id: I5ebcc7f8a06b3f0a52815d241c561bb65e036026