Move bazel Rust crate definition into separate files. #66

Job	Run time
build_attest_all (buildconfigs/key_xor_test_app.sh)	2m 12s
build_attest_all (buildconfigs/oak_containers_kernel.sh)	13m 49s
build_attest_all (buildconfigs/oak_containers_orchestrator.sh)	6m 24s
build_attest_all (buildconfigs/oak_containers_stage1.sh)	3m 43s
build_attest_all (buildconfigs/oak_containers_syslogd.sh)	5m 56s
build_attest_all (buildconfigs/oak_containers_system_image.sh)	12m 2s
build_attest_all (buildconfigs/oak_echo_enclave_app.sh)	2m 13s
build_attest_all (buildconfigs/oak_echo_raw_enclave_app.sh)	2m 26s
build_attest_all (buildconfigs/oak_functions_enclave_app.sh)	2m 25s
build_attest_all (buildconfigs/oak_functions_insecure_enclave_app.sh)	2m 20s
build_attest_all (buildconfigs/oak_orchestrator.sh)	2m 12s
build_attest_all (buildconfigs/oak_restricted_kernel_simple_io_init_rd_wrapper_bin.sh)	2m 54s
build_attest_all (buildconfigs/stage0_bin.sh)	2m 48s
	1h 1m 24s

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