Show warning when there are unsaved changes
When the detail panel shows the form and the user performs some action that would make the form to go away the Webclient should issue a warning in case the form holds unsaved changes. The warning should provide 3 options:
- Save: Saves the changes before leaving the form. This is the default action (triggered by pressing Return).
- Discard Changes: leaves the form without saving the changes.
- Close: closes the warning and stays in form. Aborts the action that causes the warning to appear. Presented as small "X" icon in upper right corner.
This is a follow-up of dmx-intern/sprint-planning#121