docs(hermetic-build): improve usability of development guide #510

Job	Run time
filter	1m 7s
build(21) except self-service clients	12m 21s
build(25) except self-service clients	12m 23s
build(8) for showcase	9m 29s
build (17)	13m 24s
showcase (21)	10m 8s
build(8) for gapic-generator-java	11m 30s
gapic-generator-java-bom	2m 34s
build(8) except for gapic-generator-java	4m 11s
dependency_analyzer_unit_test	1m 20s
build (11)	13m 57s
unmanaged_dependency_check	10m 22s
showcase (25)	10m 0s
showcase-clirr	5m 7s
showcase (17)	10m 3s
showcase (11)	9m 45s
	2h 17m 41s

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