Add environment and XDR information to the getNetwork endpoint

[wildework]

Right now getNetwork returns the following for testnet

{
    "jsonrpc": "2.0",
    "id": 8675309,
    "result": {
        "friendbotUrl": "https://friendbot.stellar.org/",
        "passphrase": "Test SDF Network ; September 2015",
        "protocolVersion": 20
    }
}

It would be helpful to supplement this response with the interfaceVersion with a range of supported SDK versions (these are embedded in a WASM custom section). Also, the version/commit for the Soroban environment and XDR that the RPC/network supports.

What problem does your feature solve?

This would allow tool developers to gracefully fail when versions become out of sync between the tool and futurenet or testnet.

What alternatives are there?

I guess you can use the protocolVersion to track down these values by going through the related repositories, but I wouldn't know how to do it.