Add possibility to save default values

[meinsiedler]

Add a "Save as default" button which saves the current settings for the user. When restarting Excel, these settings should automatically get applied.
With this feature it is possible that a user stores his favored target table format and other extended settings.

Implementation notes

• Configuration is stored in users's AppData folder
• Stored configuration will be overridden when "Save as default" button is pressed multiple times
• also consider "auto save" option so instead of "Save as default" button