[Enhancement] Provide feedback about unsuccessful user actions

[Olf0]

[Enhancement] Provide feedback about unsuccessful user actions

[buschmann23]

I ever planned to move the API part into a separate library. So I will implement this when I have that ready... (#9)

[Olf0]

Another "such action" (regularly occurring to me) is:

• When Framrekkari fails to open a slug (i.e., to load it from Transifex).
  Currently Framrekkari shows an endlessly spinning "waiting circle " in this case (there seems to be no timeout or it takes many minutes to trigger).

This occurred to me 1,5 years ago when testing issue #10 and now again, as I had a hard time loading the slugs "separate-alarm-flipover-patch-for-sailfishos-patchmanager" and "top-menu-control-patch-for-sailfishos-patchmanager" (for two days and a couple of 10 tries, but finally succeeded). BTW, their Transifex pages are https://www.transifex.com/ancelad/separate-alarm-flipover-patch-for-sailfishos-patchmanager/dashboard/ & https://www.transifex.com/ancelad/top-menu-control-patch-for-sailfishos-patchmanager/dashboard/
There seems to be some instability when opening a slug (maybe ones with long names or whatever), either at Transifex or in Framrekkari. But providing feedback about falling actions (plus a timeout, determining that an action failed) would ease testing such issues a lot.