Upgrade Shell to Statemint (with XCM Fix)

This is a follow up to Referendum 46, which failed because Polkadot did not have a default XCM version set. This protection, that the Relay Chain will not dispatch messages without a minimum safe version, was put in place after a previous vulnerability. Since this is the first cross-chain interaction that Polkadot has had, the version was not initialized.

The batch of calls contains the same two calls as Referendum 46, with an additional call to set the default XCM version of Polkadot to 2.