node: unify signing prefixes

[evan-gray]

Description and context

https://github.com/wormhole-foundation/wormhole/blob/main/whitepapers/0009_guardian_key.md defines the use of signing prefixes. However, these prefixes are currently located throughout the codebase. It would be ideal for them to live in one location.

wormhole/sdk/p2p_consts.go

Lines 4 to 9 in 2cce7a5

	HeartbeatMessagePrefix = []byte("heartbeat|")
	SignedObservationRequestPrefix_old = []byte("signed_observation_request|")
	SignedObservationRequestPrefix = []byte("signed_observation_request_000000|")
	SignedWormchainAddressPrefix = []byte("signed_wormchain_address_00000000|")
	)

wormhole/node/pkg/p2p/p2p.go

Lines 85 to 88 in 2cce7a5

	var heartbeatMessagePrefix = []byte("heartbeat|")
	var signedObservationRequestPrefix = []byte("signed_observation_request|")

wormhole/node/pkg/governor/governor_monitoring.go

Lines 560 to 562 in 2cce7a5

	var governorMessagePrefixConfig = []byte("governor_config_000000000000000000|")
	var governorMessagePrefixStatus = []byte("governor_status_000000000000000000|")

wormhole/node/pkg/accountant/submit_obs.go

Lines 183 to 185 in 2cce7a5

	var SubmitObservationPrefix = []byte("acct_sub_obsfig_000000000000000000|")
	var NttSubmitObservationPrefix = []byte("ntt_acct_sub_obsfig_00000000000000|")

wormhole/node/pkg/query/response.go

Lines 51 to 52 in 2cce7a5

	var queryResponsePrefix = []byte("query_response_0000000000000000000|")

Definition of done

The prefixes all live exclusively in the same go sdk file.