Bitcoin - Implement multi signature wallet

[olemis]

Feature description

Bitcoin multisig wallets

Is your feature request related to a problem? Please describe. Wallet does not support Bitcoin multisig wallets

Describe the solution you'd like Usability similar to Electrum

Describe alternatives you've considered There are many crypto wallets out there , but Electrum excels to be considered the right target.

Additional context

TODO: Find a golang library for Bitcoin Requires #208 This might require changes in core.Wallet interface .

Possible implementation

• [ ] Create multisig Bitcoin wallets (backend)
• [ ] Create multisig Bitcoin wallets (GUI)
• [ ] List multisig Bitcoin wallets
• [ ] Encrypt / decrypt files for multisig Bitcoin wallet
• [ ] Implement core.Wallet interface
• [ ] Implement core.Signer interface