Using network names as network url

[aryzing]

Describe the bug
Parameter name doesn't reflect the underlying data

To Reproduce
When creating a provider, such as with:

const myProvider = new RpcProvider({ nodeUrl: constants.NetworkName.SN_MAIN });

a network name, accessed under the NetworkName prop, is being assigned to a prop called nodeUrl, which should accept a URL.

Expected behavior
The prop name should match the data being assigned to it.

• If it's a network name, it should be called nodeName
• If it's a network URL, it should be called nodeUrl