CloudSigma2 ComputeService and SecurityGroupExtension

* Added the ComputeService implementation
* Added the SecurityGroup extension
* Added the San Jose region
Do you mean moving the value of the property to a constant? This is the default VNC password assigned by the provider to the created servers. The existing provider for the version 1 of the API had it already configured as a property, and it is here to keep that in the same way.