misc: refactoring

[rllola]

This PR remove a bit of code to adopt a more minimalist approach.

• [x] Create a networks.js file to avoid instantianing it in several places
• [x] In main check the config and the Dogecoin node
• [x] Rename address to pubkey
• [x] Remove some middlewares (we may re-introduce them later but a couple might not be useful to us)
• [x] Only return the pubkey and not the all key pair
• [x] In announce message use the given public key derive from the private key given in config