NEW Refactor CLI interaction with Silverstripe app #2901

Job	Run time
CI / Generate matrix	12s
CI / Context	4s
CI / 8.3 prf-low mariadb phpunit framework-core	1m 37s
CI / Check governance	0s
CI / 8.3 mysql80 phpunit framework-core	1m 58s
CI / 8.3 prf-low mariadb phpunit framework-orm	1m 40s
CI / 8.3 mysql80 phpunit framework-orm	2m 13s
CI / 8.3 prf-low mariadb phpunit cms	2m 3s
CI / 8.3 mysql80 phpunit cms	2m 0s
CI / 8.3 mysql80 phplinting	2m 46s
CI / 8.3 mysql80 phpunit framework-cache-only inmemorycache	2m 2s
CI / Dispatch tag patch release	0s
	16m 35s

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