Folder creation while offline should be possible

[OlivierS1]

Actual behavior

-Tell us what happens
Manipulating or creating folders while offline is not possible.

Expected behavior

-Tell us what should happen
When server is not reachable (ie. no Wifi), it is not possible to create a folder from within Nextcloud App.
It would be nice to be able to performs basic folder file transaction while being offline.
It would be nice to have the ability to create folders then assign files to be uploaded within the newly created folder.

Steps to reproduce

1. Phone doesn't have Wifi enabled or connection to server is unavailble.
2. Selecting + icon to create a folder.
3. Enter folder name and press OK.
   4.Error message pops-up: "The operation couldn't be completed; server is unavailable."

Environment data

Android version:
6.0

Device model:
LG-G3 LG-D852

Stock or customized system:
Stock

Nextcloud app version:
1.41.1 RC1 and Beta 20170105
Nextcloud server version:
OC 9.1

[tobiasKaminsky]

To include in #1143