Add Gas Fee Estimation with Blocknative

Adding the gas fee estimation API to the Sei documentation.

pages/dev-gas.mdx

@@ -15,6 +15,8 @@ The maximum amount of gas the user wants the transaction to use. If the gas limi
 ### Fee
 `Fee = Gas Price * Gas Limit`.
 
+To optimize your gas fee setup you can use a third-party API provided by Blocknative. Please follow the documentation [here](https://docs.blocknative.com/gas-prediction/gas-platform) to get set up.
+
 ### Maximum Gas
 
 The maximum gas limit for a transaction ensures that complex transactions do not consume excessive resources. You can find the maximum gas limits for each chain in the [Sei chain registry](https://github.com/sei-protocol/chain-registry/blob/main/gas.json) or by querying the `/consensus_params` of the RPC node itself (ex. https://rpc.pacific-1.sei.io/consensus_params).