guides: add onboarding snippets #20434

Job	Run time
setup	59s
notification	6s
specs	1m 14s
scripts	46s
client javascript@22.9.0	8m 54s
client csharp@8.0.402	5m 25s
client dart@3.5.2	4m 7s
client go@1.23.1	4m 9s
client java@8	3m 46s
client java@11	3m 48s
client java@21	4m 2s
client java@17	3m 47s
client kotlin@17.0.12	5m 54s
client php@8.3	3m 57s
client python@3.8	4m 11s
client python@3.9	4m 15s
client python@3.10	3m 53s
client python@3.11	3m 49s
client python@3.12	3m 56s
client ruby@3.3.5	3m 27s
client scala@17.0.12	7m 52s
client swift@5.9	6m 55s
client kotlin${{ (((needs.setup.outputs.RUN_MACOS_KOTLIN_BUILD == 'true') && format('@{0}', fromJSON(needs.setup.outputs.KOTLIN_DATA).version)) \|\| '') }} macos	1s
client swift${{ (((needs.setup.outputs.RUN_MACOS_SWIFT_CTS == 'true') && format('@{0}', fromJSON(needs.setup.outputs.SWIFT_DATA).version)) \|\| '') }} macos	1s
codegen	1s
check_green	1s
push_and_release	1s
	1h 29m 17s

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