feat: Add Gin framework to various packages, introducing new server structure with separate service registries for general nodes, map nodes, and reduce nodes.

pkg/map-node/node.go

@@ -0,0 +1,13 @@
+package mapnode
+
+import "github.com/gin-gonic/gin"
+
+func Start() {
+	router := gin.Default()
+	router.GET("/ping", func(c *gin.Context) {
+		c.JSON(200, gin.H{
+			"message": "pong",
+		})
+	})
+	router.Run() // listen and serve on 0.0.0.0:8080
+}