Missing section on configuring BP / full nodes

[aspiers]

https://docs.aergo.io/en/latest/running-node/configuration.html says:

There are three common modes of operation for aergo server:

• BP Node - Block provider node, which mines and propagates blocks
• Full Node - Node to get and validate all blocks
• Single Node - BP Node without peer, which uses to something like test.

We describe only single node configuration in this. More will updated for the BP Node and full node.

So currently it is not clear how to join e.g. the testnet. I see that #4 was closed but not sure what the resolution was.

[graup]

You're right, that page is missing some minimal config file for how to sync with the testnet. Normally you don't need it (the default config should suffice), but we should still explain how to do it if you want to.