Swap Zero Fee

[shoom3301]

Description
This is a part of "Solver Computed Fees" CIP.
Technically, we should change swap orders fee structure to make it the same with limit orders.

We can start working on the CORE which is keeping UI the same, but changing what the user signs:
- Changing fee to be zero
- Making sell amount to be the full sell amount (before was sell amount minus fee)
- Changing the buy amount to be = (sell amount - current fee) * Theoretical price ( 1-slippage)

Docs
https://www.notion.so/cownation/2023-10-Swap-as-Limit-orders-fee-0-5a00548015a14c9f939b934cb5e33309