Hardware Wallet detail screen

[ovitrif]

Part of #998.

Scope

Implement the Hardware Wallet detail screen:

• Savings/Spending-style overview.
• Top bar shows device name and blue BTC icon.
• Balance header.
• Transfer To Spending button.
• Grouped hardware activity list.
• Remove <device name> action with confirmation dialog:
  • Don't worry, your funds are safe and your coins won't be deleted. Bitkit will simply stop displaying the amounts in the wallet.
  • Cancel / Remove actions.
• Empty state: ₿ 0, Send/Receive only.