This includes the introduction of the --data-dir parameter instead of the --database.
Both the seed file and the database are stored in the data-dir, the database in sub-folder `database`.
Created network, storage and protocol modules. Organised
files into the modules where the belong.
xmr_btc crate moved into isolated modulein swap crate.
Remove the xmr_btc module and integrate into swap crate.
Consolidate message related code
Reorganise imports
Remove unused parent Message enum
Remove unused parent State enum
Remove unused dependencies from Cargo.toml
