[poc_uc-1] Add new file

[fxdeniz]

Provide a way to user for adding new file into system.

Steps of use case

1. Open dialog and allow user for selecting file which is about be added into db.

   • fxdeniz/XdBackup#3
   • fxdeniz/XdBackup#5
   • When adding new file check for these cases:
   • Check whether file exist in user file system #6
   • Check whether file can be opened as read only #7
   • Check whether disk size is enough for adding file to db #8
   • Check whether selected file already exist in selected files #9
   • Check whether file already added to db by user file path #10

2. Addition must be done through background task

   • Task must provide interface for setting target symbol folder #14
   • Task must provide interface for adding selected files #13
   • Task must provide interface for notifying result of each add request #15

3. If addition successful:

   • Display success message #17
   • Notify FileMonitoringSubsystem for new added file #76
   • When dialog closed refresh file explorer to show new added files #33

4. If addition failed:

   • Display error message explaining why addition failed #18

5. Group added files

   • Increase SaveGroupItemNumber #78