Setup bazel to build a WASM version of the attestation library #197

Job	Run time
build_attest_all (buildconfigs/key_xor_test_app.sh)	4m 7s
build_attest_all (buildconfigs/oak_client_android_app.sh)	51m 40s
build_attest_all (buildconfigs/oak_containers_agent.sh)	6m 48s
build_attest_all (buildconfigs/oak_containers_kernel.sh)	29m 11s
build_attest_all (buildconfigs/oak_containers_orchestrator.sh)	10m 28s
build_attest_all (buildconfigs/oak_containers_stage1.sh)	5m 42s
build_attest_all (buildconfigs/oak_containers_syslogd.sh)	8m 34s
build_attest_all (buildconfigs/oak_containers_system_image.sh)	15m 9s
build_attest_all (buildconfigs/oak_containers_nvidia_system_image.sh)	16m 31s
build_attest_all (buildconfigs/oak_echo_enclave_app.sh)	5m 1s
build_attest_all (buildconfigs/oak_echo_raw_enclave_app.sh)	4m 2s
build_attest_all (buildconfigs/oak_functions_enclave_app.sh)	4m 50s
build_attest_all (buildconfigs/oak_functions_insecure_enclave_app.sh)	4m 45s
build_attest_all (buildconfigs/oak_orchestrator.sh)	3m 59s
build_attest_all (buildconfigs/oak_restricted_kernel_simple_io_init_rd_wrapper_bin.sh)	5m 23s
build_attest_all (buildconfigs/stage0_bin.sh)	5m 56s
	3h 2m 6s

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