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
Add a binary crate `swap` that implements two nodes (Alice and Bob). With this
applied we can start up a node for each role and do:
- Bob: Requests current amounts using BTC is input
- Alice: Responds with amounts
- Bob: (mock) get user input to Ok the amounts
... continue with swap (TODO)
