DB8: Set version to 3

:Release Notes:
Set version in CMakeLists.txt to 3.0.0 from 2.0.0

:Detailed Notes:
This takes acount of the APIs which have been added since the initial
open sourced version of DB8.

:Testing Performed:
Ensure that activitymanager and keymanager still build.

:QA Notes:

:Issues Addressed:

Open-webOS-DCO-1.0-Signed-off-by: Roger Stringer <roger.stringer@lge.com>

Change-Id: I59d45920f8bb0d0a90ac16dd6d4fa255bb527940
Reviewed-on: https://g2g.palm.com/3387
Reviewed-by: Build Verification
Tested-by: Roger Stringer <roger.stringer@lge.com>
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>
Reviewed-by: Roger Stringer <roger.stringer@lge.com>