Advanced Microversion Support - Client

The Manila client needs the ability to query the Manila server for the current version and use the reported version if it falls in the range supported by the client.

The Manila client needs the following changes to support microversions:
* Maintain backwards compatibility with Kilo. When the client detects
    that the server doesn't support microversions it will fall back to
    using the v1 API.
* The --os-share-api-version option supports overriding the version.
* If 1.0 is specified as the version the client will load the v1
    client and use the server's v1 API.
* The client will send a request for the server's API version and
    determine if the client's supported versions and the server's
    supported versions overlap. If not the client will display an error
    and quit. See diagram 1 below.
* The client supports the @wraps annotation. The annotation is used
    with v2/shell.py commands to indicate the version supported by the
    command.
* If an appropriate command version isn't found for commands using
    @wraps then the client will display an error and quit.

The files in the v2 directory include the latest available client code.
The files in the v1 directory represent the client code available in the
following commit: ab49d645befd04c84272f0d24e1b604012d191dd.

Diagram 1:
  Client:
         2.5 2.8
          |-------------|
  Server1:
     2.0 2.5
      |-------------|
     Client uses version 2.5
  Server2:
               2.7 2.10
                |-------------|
               Client uses version 2.8
  Server3:
                  2.9 2.12
                   |-------------|
                  Client displays error and quits
  Server4:
     1.0 (Kilo Server)
      |-|
     Client detects pre-microversion server and loads v1 client