latency: added new library for latency stats

latency: added new library for latency stats

Add a library designed to calculate latency statistics and report them
to the application when queried. The library measures minimum, average and
maximum latencies, and jitter in nano seconds. The current implementation
supports global latency stats, i.e. per application stats.

Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
Signed-off-by: Remy Horton <remy.horton@intel.com>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>