extra/gen_rodata_ld: Add gen_rodata_ld tool. #709

Job	Run time
Build and package cores	9m 2s
Split off zephyr	8s
Split off zephyr_unoq	12s
Split off zephyr_main	9s
Split off zephyr_contrib	14s
Test zephyr_main:giga	2m 31s
Test zephyr_main:nano33ble	2m 32s
Test zephyr_main:portentac33	2m 40s
Test zephyr_main:opta	2m 27s
Test zephyr_main:portentah7	2m 30s
Test zephyr_main:niclasense	2m 27s
Test zephyr_contrib:ek_ra8d1	2m 24s
Test zephyr:unoq	2m 16s
Test zephyr_contrib:frdm_rw612	2m 18s
Test zephyr_contrib:frdm_mcxn947	2m 23s
Publish jsons	16s
Collect logs	6s
verify-core	0s
Publish core	0s
cleanup-artifacts	6s
	34m 41s

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