Folder/File based index view structure

[ubmarco]

Is your feature request related to a problem? Please describe.
The list of needs cannot be structured around files. This makes the tree harder to use.

Describe the solution you'd like
A new button like in the Git changes view that show need items in a folder/file structure.

Describe alternatives you've considered
Use a filter to show only certain needs. This however requires efforts and is clunky when navigating between folders.

Additional context

[danwos]

Would be also good if the current opened file gets highlight/selected in the view

[danwos]

It shall be possible via button to show the needs of the currently opened file only.
The view gets automatically updated, when different editor windows are opened or get the focus.

[ubmarco]

A needs type and link-structure based organisation would also be very helpful:
#50

ubCode would then also be seen more as a V-Model explorer in the sense of ISO26262 / ASPICE.