Store test scenario results in DB

*) Add new table TaskResult to store results of each test scenario

*) Add 2 new methods to DB:
task_get_detailed - returns task with results
task_result_create - create result record for task

*) Add to CLI new method that shows detailed infromation about task.

*) Add new method to Task class to append results

*) Store results into DB

implement bp db-task-track

Change-Id: I52dc6c76d44230b0685773a77601700e3d0b4f91
Merge "Store test scenario results in DB"