[UX] Use `--network-id` CLI argument instead of `NODE_ENV` environment variable to select the network

[frol]

This issue is based on the user report in Discord.

Currently, to select a network, one should set an environment variable NODE_ENV, which is an abuse of the variable in the first place, and also confusing. There is a CLI argument -~~network_id / ~~~~networkId (oh my, both aliases are alien to unix CLI practices, where kebab-case is used, i.e. ~~-network-id), which turns out to have no effect on the nodeUrl, walletUrl, and others.