Add spell command

[ferranbt]

📝 Summary

This PR introduces a new suave-geth spell command used for testing to deploy a Suave and send confidential requests to Kettles.

The spell command has two-subcommands:

$ suave-geth spell deploy <contract location>

$ suave-geth spell conf-request <addr> '<func name>'

📚 References

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• I have seen and agree to CONTRIBUTING.md

[metachris]

lstm!