Redesign the Wallet funding process

[da-kami]

Note: This ticket is still work in progress because more creative design work is needed to come up with the design specifics. That's why this ticket is an an epic - we may break it into more specific tickets after agreeing on a design.

Problems

• Multiple wallets with multiple (same or similar) actions are hard to understand for the user
• In the current prototype it can be unclear which wallet gets funded when trigging intial funding

MVP Context

Constraints:

1. The Trading wallet does not have a send/received; one can only transfer funds from the Lightning wallet into the trading wallet and from the Trading wallet back into the Lightning wallet
2. The Lightning wallet has send and receive actions
   1. [must] Fund the Lightning wallet from another existing Lightning wallet
   2. [could] The user can fund the on-chain wallet and then transfer funds into the Lightning wallet
3. There is an on-chain Bitcoin wallet that also includes send/receive (on-chain) but it is treated as "second class" citizen and the user is not encouraged to send funds into it. (In the future we can make this a more prominent feature and change this, but in the MVP the on-chain wallet does not get prominence)
   1. Moving funds between the Bitcoin and Lightning wallet and the Bitcoin and Trading wallet is our of scope

Funding needs

1. It needs to be clear to understand for the user that funding the Lightning wallet is the go to action
2. It needs be clear to the user that the Trading wallet is "attached" to the Lightning wallet, i.e. funds are moved out of or into the Lightning wallet from the Trading wallet

Note: #37 may have some influence on this ticket. E.g. a checklist with "initial steps to be done to trade" may help understand the relationship between the Trading and the Lightning wallet.

[da-kami]

This means we now have more steps until the user can trade:

1. Fund the Lightning wallet
2. Move funds into the trading wallet
3. Open a position

This is a clearer flow, but we could opt for adding a suggestion to move funds into the trading wallet upon initially funding the Lighting wallet. Here's what I have in mind:

1. User opens the app for first time
2. Users notices the action to fund the Lightning wallet
3. User funds the lightning wallet; eventually scans the invoice; the payment is incoming
4. Upon the incoming payment open a dialog that says something like: "You just receive a payment, want to use it for trading? - No Yes"?
   1. User clicksYes: jump to the screen for "funding" the Trading wallet. The user can choose how much to move to the Trading wallet there
   2. User clicks No: close the dialog

[da-kami]

Decision in short: There is only one Wallet, and to trade the off-chain wallet is to be funded. Upon triggering a Receive the user has to choose to fund on-chain or off-chain, with off-chain being encouraged.

For more details see: #43 (comment)