Adding/Handling DB specific exceptions

Added a new family of exceptions to easily differentiate the exceptions
related to database API.
Modified the way in wich exceptions are handled by the API, in order to
obfuscate the DB exceptions presented to the user.

Change-Id: Ic910549bd205eb4c2069dc5fdf2905e4ead21ffb
Closes-Bug: #1237293
Merge "Adding/Handling DB specific exceptions"