Simplify Mobidex interface

[generalpiston]

Is your feature request related to a problem? Please describe.
Mobidex is too complicated:

1. There are two sections with assets: trade and wallet
2. Creating orders and filling orders is not intuitive

Describe the solution you'd like

1. Merge trade/wallet sections into a view showing:
   a. Asset name and logo
   b. Asset price/amount depending on configuration
   c. Asset actions: buy, sell, wrap, unwrap, etc.
2. Create an "invest in market" action that lets users create orders against 0x
3. Make "orders" section about "investments" or some other better name
4. Make viewing asset details optional through a separate action

Describe alternatives you've considered

1. Keep trade and wallet separate: generally more confusing to users through empirical data.
2. Full orderbook model: users are looking for the best price usually.

Additional context