indexer: forward suins requests (MystenLabs#12268)

## Description 

refer title

## Test Plan 

test locally with http://ewr-mnt-rpc-03.mainnet.sui.io:9000/ as
underlying FN and make sure SuiNS endpoints work

```
curl --location --request POST http://127.0.0.1:3030 \
--header 'Content-Type: application/json' \
--data-raw '{
"jsonrpc": "2.0",
"id": 1,
"method": "suix_resolveNameServiceAddress",
"params": ["seanmikha.sui"]
}'
{"jsonrpc":"2.0","result":"0xe0b97bff42fcef320b5f148db69033b9f689555348b2e90f1da72b0644fa37d0","id":1}%                                                 
curl --location --request POST http://127.0.0.1:3030 \
--header 'Content-Type: application/json' \
--data-raw '{
"jsonrpc": "2.0",
"id": 1,
"method": "suix_resolveNameServiceNames",
"params": ["0xe0b97bff42fcef320b5f148db69033b9f689555348b2e90f1da72b0644fa37d0"]
}'
{"jsonrpc":"2.0","result":{"data":["seanmikha.sui"],"nextCursor":"0xce63acd667fb227282c32eeef8d63e543996df9617715649d2a68436a31161b0","hasNextPage":false},"id":1}%       
```

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
then add to the Release Notes section as highlighted during the release
process.

### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

crates/sui-indexer/src/apis/indexer_api.rs

@@ -449,19 +449,19 @@ where
         Ok(())
     }
 
-    async fn resolve_name_service_address(&self, _name: String) -> RpcResult<Option<SuiAddress>> {
-        // TODO(gegaowp): implement name service resolver in indexer
-        todo!()
+    async fn resolve_name_service_address(&self, name: String) -> RpcResult<Option<SuiAddress>> {
+        self.fullnode.resolve_name_service_address(name).await
     }
 
     async fn resolve_name_service_names(
         &self,
-        _address: SuiAddress,
-        _cursor: Option<ObjectID>,
-        _limit: Option<usize>,
+        address: SuiAddress,
+        cursor: Option<ObjectID>,
+        limit: Option<usize>,
     ) -> RpcResult<Page<String, ObjectID>> {
-        // TODO(gegaowp): implement name service resolver in indexer
-        todo!()
+        self.fullnode
+            .resolve_name_service_names(address, cursor, limit)
+            .await
     }
 }