api: v2alpha1 transaction service (#5933)

Definition:
```
service TransactionService {
  rpc List(TransactionRequest) returns (TransactionList);
  rpc ParseTransaction(ParseTransactionRequest) returns (ParseTransactionResponse);
  rpc SubmitTransaction(SubmitTransactionRequest) returns (SubmitTransactionResponse);
  rpc EstimateGas(EstimateGasRequest) returns (EstimateGasResponse);
}
```


Stream will be implemented in separate PR

api/grpcserver/config.go

@@ -28,37 +28,39 @@ type Config struct {
 type Service = string
 
 const (
-	Admin                    Service = "admin"
-	Debug                    Service = "debug"
-	GlobalState              Service = "global"
-	Mesh                     Service = "mesh"
-	Transaction              Service = "transaction"
-	Activation               Service = "activation"
-	Smesher                  Service = "smesher"
-	Post                     Service = "post"
-	PostInfo                 Service = "postInfo"
-	Node                     Service = "node"
-	ActivationV2Alpha1       Service = "activation_v2alpha1"
-	ActivationStreamV2Alpha1 Service = "activation_stream_v2alpha1"
-	RewardV2Alpha1           Service = "reward_v2alpha1"
-	RewardStreamV2Alpha1     Service = "reward_stream_v2alpha1"
-	NetworkV2Alpha1          Service = "network_v2alpha1"
-	NodeV2Alpha1             Service = "node_v2alpha1"
-	LayerV2Alpha1            Service = "layer_v2alpha1"
-	LayerStreamV2Alpha1      Service = "layer_stream_v2alpha1"
+	Admin                     Service = "admin"
+	Debug                     Service = "debug"
+	GlobalState               Service = "global"
+	Mesh                      Service = "mesh"
+	Transaction               Service = "transaction"
+	Activation                Service = "activation"
+	Smesher                   Service = "smesher"
+	Post                      Service = "post"
+	PostInfo                  Service = "postInfo"
+	Node                      Service = "node"
+	ActivationV2Alpha1        Service = "activation_v2alpha1"
+	ActivationStreamV2Alpha1  Service = "activation_stream_v2alpha1"
+	RewardV2Alpha1            Service = "reward_v2alpha1"
+	RewardStreamV2Alpha1      Service = "reward_stream_v2alpha1"
+	NetworkV2Alpha1           Service = "network_v2alpha1"
+	NodeV2Alpha1              Service = "node_v2alpha1"
+	LayerV2Alpha1             Service = "layer_v2alpha1"
+	LayerStreamV2Alpha1       Service = "layer_stream_v2alpha1"
+	TransactionV2Alpha1       Service = "transaction_v2alpha1"
+	TransactionStreamV2Alpha1 Service = "transaction_stream_v2alpha1"
 )
 
 // DefaultConfig defines the default configuration options for api.
 func DefaultConfig() Config {
 	return Config{
 		PublicServices: []Service{
 			GlobalState, Mesh, Transaction, Node, Activation, ActivationV2Alpha1,
-			RewardV2Alpha1, NetworkV2Alpha1, NodeV2Alpha1, LayerV2Alpha1,
+			RewardV2Alpha1, NetworkV2Alpha1, NodeV2Alpha1, LayerV2Alpha1, TransactionV2Alpha1,
 		},
 		PublicListener: "0.0.0.0:9092",
 		PrivateServices: []Service{
 			Admin, Smesher, Debug, ActivationStreamV2Alpha1,
-			RewardStreamV2Alpha1, LayerStreamV2Alpha1,
+			RewardStreamV2Alpha1, LayerStreamV2Alpha1, TransactionStreamV2Alpha1,
 		},
 		PrivateListener:        "127.0.0.1:9093",
 		PostServices:           []Service{Post, PostInfo},