Create a restore option in the GUI

[joente]

Implement a restore option in ThingsDB GUI.

When opening the restore model, the following should be done:

1. As a user you should be able to enter a filename and enable/disable a take_access option.
2. When a filename is entered and the restore button is pressed, the following should be done:
3. Check with nodes_info() if there is more than one node and if so, check if all nodes have the latest event ID stored on disk. (stored_event_id must be equal to committed_event_id on all nodes)
4. Check if all nodes have status READY
5. As long as the checks above are not ok, a message should appear like: Waiting for node x ... and every 5 or 10 seconds the gui can ask an update with nodes_info()
6. When the checks are fine, the gui should perform the restore(...); command

• If successful, a model should appear with a message and a button which cannot be closed and when pressed will forward to the login page. (a new login is required after a successful restore)
• If failed, the GUI should display the error message of ThingsDB. (this may be that for example the given file does not exist)

[AnjaBruls]

Added in Release v0.2.5