WF-1703: Modified the code for task completion to add user and to remove roles.
Resolved WF-1706
WF-1705: Modified the code to enable tracking of last active date and last assigned date for tasks.
WF-1705: Modified the code to enable null value for last assigned date for tasks with no assignment.
Fixed NPE when specified role does not have any assigned users.
CON-941: Added attribute audit type
DASHBOARD-120, DASHBOARD-121: Added new APIs for dashboard widgets.