Add simple API that returns list of share protocols that are supported

Manila has support for different share protocols. But it is very unlikely to have cloud where all of them are available at once (appropriate back-ends are set up). Manila allows to disable some share protocols by means of config file.

But to get know whether we are able to use some share protocol or not we can only try create share and get response with error that it is not supported. And it is not proper approach to get such information.

So, this BP is dedicated to track activity about adding of new API which provides list of share protocols that are supported by Manila installation.