Add script for migrating from other CNI to Antrea #28882

Job	Run time
Check whether tests need to be run based on diff	17s
Build Antrea image to be used for Kind e2e tests	18m 36s
Build Flow Aggregator image to be used for Kind e2e tests	6m 42s
E2e tests on a Kind cluster on Linux with non default values (proxyAll=true, LoadBalancerMode=DSR...	1h 4m 52s
E2e tests on a Kind cluster on Linux	55m 19s
E2e tests on a Kind cluster on Linux with all features enabled	1h 9m 4s
E2e tests on a Kind cluster on Linux (hybrid)	36m 21s
E2e tests on a Kind cluster on Linux for Flow Visibility	26m 58s
E2e tests on a Kind cluster on Linux (noEncap)	35m 45s
NetworkPolicy conformance tests on a Kind cluster on Linux	10m 15s
API compatible with client version N-1	8m 56s
API compatible with client version N-2	9m 13s
Upgrade from Antrea version N-1	9m 13s
Upgrade from Antrea version N-2	9m 7s
Validate metrics in Prometheus document match running deployment's	2m 23s
Delete uploaded images	0s
	6h 3m 1s

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