cynara: rewrite class using cynara async API for parallel processing

cynara: rewrite class using cynara async API for parallel processing

Cynara class method check() can now be called in parallel by multiple
threads. Each call blocks until it gets a response.

This is a first step toward making security-manager multi-threaded, for
processing multiple requests in parallel.

Cynara class remains a singleton for now, but eventually there will be
single instance constructed (and destructed) from the main thread and
called for checks from separate threads processing user requests.

Change-Id: Ie1f55b9610caf45dc0df06dbd713070d39ccac07
Signed-off-by: Rafal Krypa <r.krypa@samsung.com>