rpcsrv: add SessionEnabled, MaxIteratorResultItems to getversion

Extend getversion RPC response with RPC server settings (SessionEnabled,
MaxIteratorResultItems).Port neo-project/neo-modules#878.

Close #3276

Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>

pkg/neorpc/result/version.go

@@ -19,6 +19,13 @@ type (
 		Nonce     uint32   `json:"nonce"`
 		UserAgent string   `json:"useragent"`
 		Protocol  Protocol `json:"protocol"`
+		RPC       RPC      `json:"rpc"`
+	}
+
+	// RPC represents the RPC server configuration.
+	RPC struct {
+		MaxIteratorResultItems int  `json:"maxiteratorresultitems"`
+		SessionEnabled         bool `json:"sessionenabled"`
 	}
 
 	// Protocol represents network-dependent parameters.

pkg/neorpc/result/version_test.go

@@ -42,6 +42,10 @@ func TestVersion_MarshalUnmarshalJSON(t *testing.T) {
             "validatorscount": 7,
             "hardforks": [{"name": "Aspidochelone", "blockheight": 123}, {"name": "Basilisk", "blockheight": 1234}]
         },
+        "rpc": {
+            "maxiteratorresultitems": 100,
+            "sessionenabled": true
+        },
         "tcpport": 10333,
         "useragent": "/NEO-GO:0.98.6/",
         "wsport": 10334
@@ -60,6 +64,10 @@ func TestVersion_MarshalUnmarshalJSON(t *testing.T) {
             "validatorscount": 7,
             "hardforks": [{"name": "HF_Aspidochelone", "blockheight": 123}, {"name": "HF_Basilisk", "blockheight": 1234}]
         },
+        "rpc": {
+            "maxiteratorresultitems": 100,
+            "sessionenabled": true
+        },
         "tcpport": 10333,
         "useragent": "/Neo:3.1.0/",
         "wsport": 10334
@@ -69,6 +77,10 @@ func TestVersion_MarshalUnmarshalJSON(t *testing.T) {
 		WSPort:    10334,
 		Nonce:     1677922561,
 		UserAgent: "/NEO-GO:0.98.6/",
+		RPC: RPC{
+			MaxIteratorResultItems: 100,
+			SessionEnabled:         true,
+		},
 		Protocol: Protocol{
 			AddressVersion:              53,
 			Network:                     860833102,

pkg/services/rpcsrv/server.go

@@ -868,6 +868,10 @@ func (s *Server) getVersion(_ params.Params) (any, *neorpc.Error) {
 		TCPPort:   port,
 		Nonce:     s.coreServer.ID(),
 		UserAgent: s.coreServer.UserAgent,
+		RPC: result.RPC{
+			MaxIteratorResultItems: s.config.MaxIteratorResultItems,
+			SessionEnabled:         s.config.SessionEnabled,
+		},
 		Protocol: result.Protocol{
 			AddressVersion:              address.NEO3Prefix,
 			Network:                     cfg.Magic,