docs(playwright-engine): add UI and CLI guides and migration recipe #6506

Job	Run time
config-e2e	1s
Build docker image	5m 37s
Agent unit tests	1m 8s
CLI unit tests	39s
WebUI unit tests	1m 53s
API Server unit tests	2m 32s
Test examples (collector)	45s
CLI smoke tests (local)	50s
CLI e2e tests (8, 0)	1m 24s
WebUI End-to-end tests (1)	2m 37s
CLI smoke tests (docker)	45s
Test examples (tracetest-jaeger)	39s
CLI e2e tests (8, 1)	1m 22s
WebUI End-to-end tests (2)	2m 39s
Test examples (tracetest-opensearch)	7m 26s
CLI e2e tests (8, 2)	1m 33s
WebUI End-to-end tests (3)	2m 40s
Test examples (tracetest-tempo)	45s
CLI e2e tests (8, 3)	1m 29s
Tracetesting API Server (InMemory)	4m 2s
WebUI End-to-end tests (4)	2m 32s
Test examples (tracetest-provisioning-env)	44s
WebUI End-to-end tests (5)	3m 43s
CLI e2e tests (8, 4)	1m 19s
WebUI End-to-end tests (6)	2m 38s
CLI e2e tests (8, 5)	2m 47s
Tracetesting API Server (NATS)	3m 53s
WebUI End-to-end tests (7)	2m 31s
CLI e2e tests (8, 6)	1m 28s
WebUI End-to-end tests (8)	2m 33s
CLI e2e tests (8, 7)	3m 35s
	1h 8m 29s

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