Enable service fee on Redeem

[loonggamma]

Context
After Mainnet bridge v1 is launched, in up to 1 month after we will initiate the collection of service fees on the Redeem flow, the 'claim' transaction step.

The ability to set the service fee is already implemented on the Smart Contract. The issue concerns testing and implementing the cost of service fee in the frontend.

User flow

1. User arrives to the index page.
2. User connects wallets and selects the Redeem flow (Massa -> Ethereum)
3. User enters an amount to redeem (user didn't receive any errors of insufficient balance)
4. User sees the bridge service fee of N% applied to his token amount. User understands the total amount of token he will receive after deducing the service fee.
5. User sees the bridge fee and receiving amount for each active claim.

How to

• Test the Backend and Smart Contract functionality of the service fee imposed on Redeem. Implement needed changes if any.

• Design the solution on the UI that is easy to understand for the end-user redeeming tokens. @LucasF243
  That means: user must understand: the amount of service fee we take in token + the receiving amount on his wallet.
  a. User should know this before initiating the approve/burn operation on Massa.
  b. User should have the same info, once he is requested to sign the Claim operation: 1. from main flow, and 2. for each active claim on the Claim page.

• Implement the frontend based on designs.

Technical details
Give the technical insights so anyone in the team can tackle the tasks - Dev

QA testing
Does this task require some QA tests ?
If yes, explain how to validate it