Feature: Cloud storage with version control

[sconklin]

From @DeadlyDad on October 13, 2017 6:16

Add feature to save and retrieve files stored on an online cloud service. Enables version tracking of patterns, with "commit" comments, etc.

Suggestion: Use the code from LibreOffice's content management interoperability system.
CMIS info here: (https://en.wikipedia.org/wiki/Content_Management_Interoperability_Services). Demo here: (Demo).
More links:

• https://help.libreoffice.org/Common/Using_Remote_Files
• https://help.libreoffice.org/Common/Using_Remote_Files_1
• https://wiki.documentfoundation.org/Development/GSoC/Successfully_Implemented_Ideas#Connection_to_SharePoint_and.2For_Microsoft_OneDrive\
• https://github.com/LibreOffice/core/tree/dcc92a7cb5aa1faa711c8da7f7d8ecee0a192c25/external/libcmis

Copied from original issue: valentina-project/vpo2#768

[KimMF]

coordinate with #178