Stellar - Implement standard wallet

[olemis]

Feature description

Bitcoin standard wallets

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

Describe the solution you'd like For usability , research how popular wallets work

Additional context

TODO: Find a golang library for Stellar Requires #323

Possible implementation

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