Harmonize notation and documentation

[asonnino]

• Document public structs and fields, so that cargo doc produces something nice.
• Harmonize variable names (eg. voting_rights)
• Rename Parameters into something like Node, NodeConfig, or NodeSpawner and/or incorporating more of the parameters of spawn(..)
• Remove the node crate and include the main functions into the respective crates (eg. librabft-v2)