Adapt pbc.c to current json rpc spec (#1857) #96

Job	Run time
bullseye armv7 / build	3m 18s
bookworm armv7 / build	5m 11s
bullseye armv7 / test (run_install_common.sh)	14m 7s
bullseye armv7 / test (run_install_faststartup.sh)	9m 16s
bullseye armv7 / test (run_install_webapp_local.sh)	15m 39s
bullseye armv7 / test (run_install_webapp_download.sh)	15m 0s
bullseye armv7 / test (run_install_libzmq_local.sh)	23m 47s
bookworm armv7 / test (run_install_common.sh)	14m 15s
bookworm armv7 / test (run_install_faststartup.sh)	10m 13s
bookworm armv7 / test (run_install_webapp_local.sh)	14m 0s
bookworm armv7 / test (run_install_webapp_download.sh)	13m 59s
bookworm armv7 / test (run_install_libzmq_local.sh)	24m 38s
bullseye armv7 / cleanup	3s
bookworm armv7 / cleanup	3s
	2h 43m 29s

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