VDiff: Add control for start/resume and stop #930

Job	Run time
Set push variable	1s
Build and push vttestserver (mysql80)	2m 5s
Build and push lite (latest)	2m 16s
Build and push lite (percona80)	2m 14s
Build and push (bullseye, vtadmin)	1m 14s
Build and push (bullseye, vtorc)	38s
Build and push (bullseye, vtgate)	45s
Build and push (bullseye, vttablet)	31s
Build and push (bullseye, mysqlctld)	41s
Build and push (bullseye, mysqlctl)	40s
Build and push (bullseye, vtctl)	42s
Build and push (bullseye, vtctlclient)	31s
Build and push (bullseye, vtctld)	1m 20s
Build and push (bullseye, vtctldclient)	41s
Build and push (bullseye, logrotate)	22s
Build and push (bullseye, logtail)	13s
Build and push (bullseye, vtbackup)	43s
Build and push (bullseye, vtexplain)	42s
Build and push (bookworm, vtadmin)	1m 14s
Build and push (bookworm, vtorc)	28s
Build and push (bookworm, vtgate)	29s
Build and push (bookworm, vttablet)	46s
Build and push (bookworm, mysqlctld)	40s
Build and push (bookworm, mysqlctl)	36s
Build and push (bookworm, vtctl)	51s
Build and push (bookworm, vtctlclient)	43s
Build and push (bookworm, vtctld)	1m 7s
Build and push (bookworm, vtctldclient)	40s
Build and push (bookworm, logrotate)	21s
Build and push (bookworm, logtail)	26s
Build and push (bookworm, vtbackup)	36s
Build and push (bookworm, vtexplain)	26s
	25m 42s

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