cli: Handle Solana initialization flow for undeployed program and SPL Multisig mint authority (wormhole-foundation#649)

This PR adds:
* Update `set-mint-authority` command to work as described in [this comment](wormhole-foundation#649 (comment))
* Update `create-spl-multisig` command to work similar to `set-mint-authority` and is described in the same comment
* Update `deploySolana` to handle NTT initialization with current mint authority being valid SPL Multisig
* Add `checkSolanaValidSplMultisig` helper that checks if address corresponds to valid SPL Multisig

Author: nvsriram