Fraud reporting

[dwasse]

Description

Adds fraud reporting functionality to the guard.

Handles these cases as well as updating agent statuses.:

Fraud type	Agent	Fraud proving	Fraud reporting	Description
Invalid Snapshot	Notary/Guard	verifyStateWithSnapshot	submitStateReportWithSnapshot (N)	Snapshot having State not matching Origin
Invalid Attestation	Notary	verifyAttestation	submitAttestationReport	Attestation that was never created in Summit
Attestation from Invalid Snapshot	Notary	verifyStateWithAttestation	submitStateReportWithAttestation	Attestation having State not matching Origin
Attestation from Invalid Snapshot	Notary	verifyStateWithSnapshotProof	submitStateReportWithSnapshotProof	(alternative way to prove/report fraud)
Invalid Receipt	Notary	verifyReceipt	submitReceiptReport	Receipt that doesn't match Destination

[ChiTimesChi]

Similarly, could this be later further abstracted as DomainClient.GetAgentStatus()?

[dwasse]

One more aside, it's not a major point but can we figure out what's reordering import/doing stuff like this and disable it or find a way to make our lint workflow force standardization?

Regarding imports, my recommendation would be we add a precommit hook that runs something like this:

find . -name "*.go" -exec goimports -w {} \;

That way regardless of editor choice we will have gofmt-styled code as well as standardized import ordering (goimports is a superset of gofmt that includes import organization).

cc @trajan0x