Add abstraction method of processTxs to StateDB

- Update GHA lint.yml increasing timeout time to avoid GHA Lint errors
- Update common.BatchNum & common.Idx & common.Nonce usage in StateDB
- Add abstraction method of processTxs to StateDB
    - Which will be used by Synchronizer & BatchBuilder

common/zk.go

@@ -58,3 +58,7 @@ type ZKInputs struct {
 type CallDataForge struct {
 	// TBD
 }
+
+type ExitTreeLeaf struct {
+	// TBD
+}