Provide config to stellar-core as xdr instead of json #541

Job	Run time
amd64 / build-stellar-core	22s
amd64 / build-rs-stellar-xdr	6m 53s
amd64 / build-stellar-horizon	2m 56s
amd64 / build-stellar-friendbot	42s
amd64 / build-stellar-soroban-rpc	47s
arm64 / build-rs-stellar-xdr	1h 0m 10s
arm64 / build-stellar-core	37s
arm64 / build-stellar-friendbot	2m 2s
arm64 / build-stellar-soroban-rpc	40s
arm64 / build-stellar-horizon	7m 14s
amd64 / build	4m 7s
amd64 / test (pubnet)	1m 9s
amd64 / test (local)	1m 31s
amd64 / push-pr	42s
amd64 / push-release	0s
arm64 / build	6m 35s
arm64 / test (pubnet)	1m 16s
arm64 / push-pr	55s
arm64 / test (local)	2m 15s
arm64 / push-release	0s
manifest / push	6s
complete	1s
	1h 41m 0s

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