[usecase-webapi] Improve content usecase

- Scan complete to a pop up, not open in new page.
- Organize result to a table.
- Default show get Directory result.
- Update the button to "Open Dir".
- Fail Reason: DB connection error.

Impacted TCs num: New 0, Update 1, Delete 0
Unit test Platform: [Tizen-IVI]
Test result summary: Pass 0, Fail 1, Blocked 0
Merge pull request #646 from JianfengXu/xujf/content/update

[usecase-webapi] Improve content usecase