Add support for Soroban external calls 🎉 #7061

Job	Run time
Linux x86-64	43m 57s
Repolinter	13s
Docs	1m 15s
Container Image	11m 46s
Linux Arm	19m 33s
Mac Arm	10m 32s
Mac Intel	1s
Stdlib	3s
Windows	29m 46s
Mac Universal Binary	0s
Soroban Integration test	10m 56s
Solana Integration test	3m 17s
Polkadot Integration test	6m 45s
Anchor Integration test	5m 37s
Polkadot Integration test with subxt	4m 44s
Visual Code Extension	2m 19s
Coverage report	2m 32s
	2h 33m 16s

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