[CHANGE] Create a graphical user interface

[steffenfritz]

Describe the solution you'd like FileTrove should have a graphical user interface that gives the same controls and status views like the command line interface.

There are three options at the moment:

i) provide a REST API and provide a web user interface ii) create a fat client using the fyne library (https://fyne.io/) iii) create a fat client using another library

[steffenfritz]

Won't implement at the moment as no feedback of users if really needed.