feat: implement handling and execution of oracle data

[noot]

implement handling of oracle data received via the execution API.

see relevant contract for context: https://github.com/astriaorg/astria-oracle-contracts/blob/main/src/AstriaOracle.sol

flow is as follows:

• the AstriaOracle contract is deployed on the rollup and the address is set in genesis
• when the rollup receives RollupData.OracleData via the execution API, which consists of a vector of price updates, it converts these into contract calls to AstriaOracle.
• if the currency pair in the update is not initialized in the contract, it calls initializeCurrencyPair before calling updatePriceData. this is needed to set the decimals for that pair, which is not updated once the pair has been initialized.
• if a block does not contain any oracle data, then no price updates happen for that block, but everything else gets executed as normal.

other changes:

• renamed DepositTx to InjectedTx, as the same type is now being used for deposits and oracle updates. it was not necessary to create a new type, as the previous erc20 calls being done by the DepositTx were generic to what they were calling.
• split out the grpc/execution/validation.go validation and conversion function into separate functions for each RollupData type, no logic was changed for Deposit/SequencedData.

todo:

• need to test this end to end and determine gas amounts for the oracle contract calls. updatePriceData will be dependent on the number of prices being updated.