Implement launch protocol for changing network

[slaweet]

Expected behaviour

It should be possible to switch between mainnet, testnet and a custom node with URL search params using network keys from https://github.com/LiskHQ/lisk-wallet/blob/rebranding/src/constants/networks.js
The following options should be supported:

• ?network=mainnet
• ?network=testnet
• ?network=customNode&address=http://localhost:4000 (where address is any valid address)

Network select and address input on login page should be removed because for the vast majority of users it is an unnecessary clutter.

Actual behaviour

There is a network select and address input on login page.

[slaweet]

Solved in #47