Limited thread pool size using custom parameter in CCCC properties

Following changes were made:

1. Added thread pool size as a mandatory property of the checker
2. Refactored ConsistencyCheckingProcess.java to use only one thread pool.
3. Added getter to obtain the specified size of the thread pool from configuration.

Closes af3#4490 (closed)

Issue-ref: 4490 Issue-URL: af3#4490 (closed)

Signed-off-by: Mykhailo Riabets riabets@fortiss.org