Implement token tracking

[Zimonzk]

Send, receive, and display balance of ERC20 tokens.

[koraykoska]

The token tracking screen is part of the settings screen which I'm working on right now. It will provide a way to track new tokens and show already tracked ones for the currently selected network.

Displaying balances is part of the wallet details screen.

[Zimonzk]

n1

[koraykoska]

The list of ERC20 tokens for accounts is not implemented yet. Tracking works as it should.

[koraykoska]

Btw, maybe we should get all amounts and only display tokens with more than 0 for the selected account. If not we should at least sort by value descending.