Add standard ObjectStorage support

[fspezi]

I developed primary features for Swift (ObjectStorage).

Swift client developed features:

• Containers list
• Container content
• Get / Set container metadata
• Get object (alias file)
• Update object
• Delete object
• Get / Set object metadata
• Check file exists

I have not able with virtualized test. Then I developed a private Test project where Swift client call the Swift server of my OpenStack service provider (www.ovh.com).

PS: I hope that this work will be integrated into main project.