Add hybrid synchronisation and local boxes handling

[capt-nemo429]

Combines light and full synchronization to keep track of all owned boxes and transactions locally while maintain fast sync times. This feature will also serve as basis to 'Transactions history' tab (#44).

Todo

• Add UTxO data model
• Add transactions data model
• Migrate to backend API v1
• Port backend to GraphQL #37
• Add EIP-29 parser
• Add full sync mechanism
• Add Transactions history tab #44
• Add full and light box/balance fetching mechanism based on the status of the full sync process.