Nothing calls Type() on a driverapi.Driver. Network.Type() and
Network.Driver() report the name the driver was registered under,
not the driver's Type(). The only caller of a driver's Type() method
was the Windows overlay driver calling its own, which returns the
package's NetworkType constant.
Remove the method from the interface and its implementations, and
the tests that only asserted its return value. The remote driver no
longer needs to remember its plugin name.
Assisted-By: Claude Opus 5.5
Signed-off-by: Cory Snider <csnider@mirantis.com>