Added database adapter abstract service factory.

Change-Id: I35ed79abc898088c50d40467d6e64726e433e9f7
Removed redundant else statement and redundat condition in factory method.

Change-Id: Ia6882123128c1752151f4c4560cb8d1fcb57efa5
Added test case for database adapter abstract service factory.

Change-Id: Id77938e0298d3b214c40db7f2325f5b1efd14d81
Added db.adapters section for multiple adapters configuration. Improved validation for existing adapter configuration. Updated unit test.

Change-Id: I2ae710320d34a2fb888fcce49969cb776b27b5a7
[#3933] CS fixes
Merge branch 'feature/3933' into develop

Close #3933