fee-balancer lambda function

[eugypalu]

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Resolves #1528

What is the new behavior?

• Fee Adjustment:
  • It compares the relayers' current total balance with previous balances.
  • If the current balance plus the actual fee is less than the previous balance, the base fee is increased by 12.5%.
  • If the current balance plus the actual fee exceeds the previous balance plus an acceptable earning percentage, the base fee is decreased by 12.5%.
  • If neither condition is met, the base fee remains unchanged.

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