CHORE: Remove diff1 from codebase #1611

Job	Run time
build	14m 1s
integration-test-providers	8s
integrtests-diff2 (AZURE_DNS)	5m 12s
integrtests-diff2 (DIGITALOCEAN)	4m 41s
integrtests-diff2 (CLOUDFLAREAPI)	7m 35s
integrtests-diff2 (GCLOUD)	3m 41s
integrtests-diff2 (GANDI_V5)	5m 5s
integrtests-diff2 (BIND)	2m 47s
integrtests-diff2 (HEDNS)	6m 57s
integrtests-diff2 (HEXONET)	3m 22s
integrtests-diff2 (NAMEDOTCOM)	4m 56s
integrtests-diff2 (POWERDNS)	6m 3s
integrtests-diff2 (ROUTE53)	3m 54s
	1h 8m 22s

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