Draft: Export control mockup

This is the draft for an mockup for export control fields.

It contains some changes compared to the feature-restructure-frontend branch:

• it adds fields for owner (section), country & comment for the basic data
• it adds an additional tab export control
• dual use is now on the export control tab

Please note the following things:

• I found this list here (http://www.davros.org/misc/iso3166.txt) for the ISO codes of the countries
• The country list is frontend only. It would make sense to put it into the CV.
• The owner list is currently only hardcoded in the frontend as well (3 GFZ sections at the moment)
• Dual use is currently just a boolean value (as it is in GIPP)
• I struggle with some of those translations (Warentarifnummer?)
• I added another comment field as I think there will be different purposes between description for the sensor & sensorML (description field) and the comment for the export control (comment field)

I tried to follow the split that Tino Neßlinger suggested in his excel file (Geraeteliste_Exportkontrolle_Muster_Layout.xlsx):

• the green coloured columns are in the basic data tab
• the blue coloured columns are in the export control tab
• the attachments from the blue coloured columns would be solved with the overall attachments (currently only external urls are supported; Willi works currently on the upload options at GFZ; Kotyba wrote something to use minio in the docker setup - that would be the overall fallback)
• As we currently don't have visibility restrictions all of those fields can be viewed by the users - I guess this is something to change for later (maybe only restricted visibility of the export control tab, maybe another overall view (table?) for this data)