Basic app structure

[svub]

Setup basic Vue/Ionic app structure for hybrid app.

The app needs slots for:

• [x] Contact list
• [x] Contact details
• [x] Add new contact (scan code)
• [x] Be added as a contact (show QR code)

For simplicity, advanced aspects such as a settings panel or a map view to visualize the location of all contacts are left out.

[svub]

QR code stuff is for later.