Estimate gas price

Currently, the gas estimation is handled by taking the median of the last 100,000 transactions
If a user wants to prioritize their transaction and is willing to pay, they can pay more
than the gas price. If they're willing to wait longer, they can pay less. Note that the
gas price moves with the fee market, and should only increase when demand outweighs supply.

If there have been no transactions in the last 100,000 transactions, the price will be 1.