Chore(standalone): reuse contract_methods logic (#830)

## Description

This is a follow-up PR from #827 . In this PR we make the standalone
engine reuse the logic that was isolated from the contract in that PR.
One key thing to notice about this change is the raw bytes that would be
passed to the on-chain contract as input are now also passed to the
standalone engine. This will help enable the hashchain to work
identically both on-chain and off-chain. Additionally, the output from
all methods is captured in the IO instance. We do not yet make use of
this, but in a follow-up PR this will also be a necessary feature to
ensure the hashchain works properly.

## Performance / NEAR gas cost considerations

N/A standalone engine changes only

## Testing

Existing tests.

## Additional information

Note: the `TransactionKind::raw_bytes` method is only used in tests and
for backwards compatibility. After a full re-index of the Borealis state
(which will be needed to compute the hashchain history anyway) this
method will not be used in production (i.e. we are not de-serializing +
re-serializing the input on every transaction, that would be very
inefficient).

engine-standalone-storage/src/relayer_db/mod.rs

@@ -103,7 +103,7 @@ where
         env.random_seed = block_metadata.random_seed;
 
         let args = SubmitArgs {
-            tx_data: transaction_bytes,
+            tx_data: transaction_bytes.clone(),
             ..Default::default()
         };
         let result = storage.with_engine_access(block_height, transaction_position, &[], |io| {
@@ -154,6 +154,7 @@ where
             attached_near: 0,
             transaction: crate::sync::types::TransactionKind::Submit(tx),
             promise_data: Vec::new(),
+            raw_input: transaction_bytes,
         };
         storage.set_transaction_included(tx_hash, &tx_msg, &diff)?;
     }
@@ -265,6 +266,7 @@ mod test {
                         attached_near: 0,
                         transaction: TransactionKind::Unknown,
                         promise_data: Vec::new(),
+                        raw_input: Vec::new(),
                     },
                     &diff,
                 )