Add --quoted option to swift-temp-url

If you have a path with special characters it may be easier to hand them to
swift-temp-url prequoted than try to escape them on the command line.  By the
time common.middleware.tempurl gets ahold of the path it's unquoted so we do
the same before calculating the hmac but still use the pre-quoted path output
to the commandline.

Change-Id: Ia1a9666e487b1e70e4db7cd597bc6a1027e3e918
Merge "Add --quoted option to swift-temp-url"
isolate representation from content in GET request

Container server representation of data (received from backend) is isolated into `create_listing()` call.
GET() method will call `create_listing()` when it's ready to create a serialized object listing.
It will allow us to customize that representation: get different listing, if backend supports more interesting queries, for example.

Change-Id: I4fa03357d3d9e697bc3e1fb5da42d7572c6ae9b3
isolate object update logic from container PUT

To further extend pluggble container backends we need to have better interface
for updating object info in a container DB.
Each object has `name`, `timestamp` and metadata, the metadata is taken from the request headers, usually
The new `object_update()` method allows us to isolate metadata extraction.
We can push more logic there if backend supports smarter PUTs (more metadata, for example).

Change-Id: I1aae3e73a56c3800ccd7a8d4f818c518b5118bb1