Janosch/dev

[jgraef]

This contains commits from paberr/structure, but I also implemented some other stuff:

• Sub-crate for an executable that reads a config TOML file and starts a node.
• TestNet NetworkInfo
• UserAgent field can be parsed and sent. The UserAgent can be configured in the config and is currently set to core-rs/dev (native; Linux x64)
• std::error::Error implementation for SerializingError
• ConsensusAgent requests the Mempool of other peers.
• ConsensusAgent subscribes to Any and thus receives new blocks and txs

Since this Pull Request contains changes from paberr/structure I don't expect it to be merged right now. But you can merge it later, when the restructuring is done.

[paberr]

Has been manually merged with paberr/structure code in new branch paberr/merged. 👍