WIP kvs-watch: do not load all KVS blobs at once #10053

Job	Run time
validate commits	11s
python linting	34s
spelling	8s
Generate build matrix	8s
bookworm - test-install	12m 33s
bookworm - 32 bit	13m 6s
noble - test-install	12m 31s
el9 - test-install	12m 1s
alpine - test-install	12m 14s
fedora40 - test-install	12m 9s
jammy - test-install	11m 31s
focal - py3.8	16m 59s
bookworm - gcc-12,content-s3,distcheck	17m 42s
fedora40 - clang-18	16m 19s
coverage	23m 41s
el8 - ascii	19m 0s
el8 - test-install	14m 4s
el8 - system,coverage	7m 34s
inception	21m 27s
flux-pmix check	12m 57s
flux-sched check	6m 57s
flux-accounting check	4m 30s
macos build only	3m 20s
flux-pam check	4m 10s
Generate docker manifest	0s
	4h 15m 46s

Provide feedback