Obs App - Changed file viewing url from readDoc to file_detail

**Currently uploaded file in marker :**
- Redirected to *readDoc*
- But if file is corrupt or not uploaded successfully file rendering gets affected.


**Now *url* is changed to *file_detail*:**
- So every uploaded file will have generic detail view.
- If file format is supported then it will be displayed/played in the browser itself otherwise user can download the file.