Add or delete files and reference files to/from a project or task

It should be possible to add new files and / or reference files to a project or task.

Thoughts:

• List existing source files in the source file tab and reference files in the reference file tab
• Make it possible to delete them there or add new ones there
  • New ones will be added as new segments to the segment table at the bottom.
  • Deleted ones will simply be deleted from everywhere they are located
    • effects segment count
    • invalidates analysis (point user to this!)
    • what are the effects on segment_history?
• so far xliff originating from okapi are listed in the bilingual tab.
  • Does that make sense?  For what?
  • Should we remove the bilingual tab and put xliff that are actually provided as source files in the source file tab with all functionality that is so far implemented for them?

Points after discussion 27.03.2024

1. When  file is removed and it is linked to visual file, what will happen? Will the not found message be shown when the user clicks on non-existing segment in the layout?
   - This must be tested.
   
 2. Pivot: we can not add new pivot files but we are able to remove pivot files.
   - You can trigger pivot pre-translation to pre-translate the pivot for the segment

 
 3. Remove the export translator packate and reimport translator package from the tab panel
    - show the text in the bilingual files in the download page and also in the reimport popup
    
  Affect on adding or removing file
  
   - task progress and user progress - recalculate
   - repetitions - recalculate
   - analysis - invalidate analysis with an invalid flag plus adding a message on DB and UI, why it is invalid

   - task assignment to ranges of segments. What will happen if we remove file which is in a range of user assign segments

   - evaluate soft-delete as possible way of implementation for "deleted" segments