Close the default `ClientFactory` after a server stops in Spring integration

[ikhoon]

Motivation:

I tried to add a graceful shutdown timeout to not immediately close the default ClientFactory. https://github.com/line/armeria/pull/5718#discussion_r1624232941 However, it is a breaking change and no agreement has been reached on the default behavior.

I think that #5718 may take some time to be merged or may not be merged.

This problem can be solved more easily in Spring Boot. Spring Boot starts the application in the main method and terminates with JVM shutdown. By shutting down the default ClientFactory using SpringApplicationShutdownHook, the graceful shutdown can be supported without breaking changes for Spring integration, which is used by most users.

Modifications:

• Use SpringApplicationShutdownHandlers to close the default ClientFactory for Spring integration.

Result:

In Spring integration, the default ClientFactory is now gracefully closed after the server is shut down.

[github-actions[bot]]

🔍 Build Scan® (commit: 781fb303dcd5beee50f83272c8141075ce4adb0e)

Job name	Status	Build Scan®
build-windows-latest-jdk-21	✅	https://ge.armeria.dev/s/lzmzyei47rrhg
build-self-hosted-unsafe-jdk-8	✅	https://ge.armeria.dev/s/oagidho7ajthi
build-self-hosted-unsafe-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/l5t5zstec5z3y
build-self-hosted-unsafe-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/bw7rfl7v7hsi4
build-self-hosted-unsafe-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/spdfphqikr7yw
build-self-hosted-unsafe-jdk-17-leak	✅	https://ge.armeria.dev/s/wukc2dqpz37ao
build-self-hosted-unsafe-jdk-11	✅	https://ge.armeria.dev/s/3h76hk53qokfm
build-macos-12-jdk-21	✅	https://ge.armeria.dev/s/6ie5643aehvde

[minwoox]

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