Improvements for fragment management in OpenFLUID apps

[Arthoni]

Adding a fragment in DevStudio

• [x] #1109 (minor fix)
• [x] Automatic submodule management when creating a new fragment
• [ ] Inclusion strategy choice: inplace / in workspace / in userdata

Removing a fragment in DevStudio

• [x] Cleaning operations refactoring
• [ ] add progress bar for delete operations
• [x] Unsaved files case: check if any open and changed file from the fragment before triggering the removal operation to avoid removal if user says "cancel"?

[Arthoni]

About cleaning operations refactoring

Move all actions to global window since have effects on global window through a "fragmentRemovalAsked" signal? (changing action from SLOT to SIGNAL, follow "deleteWareAsked" logic)