迁移并重构项目，优化了执行流程

internal/Func/CheckNodes.go

@@ -0,0 +1,18 @@
+package Func
+
+import (
+	"SafeLine-Acme/internal/class/SafeLine"
+	"time"
+)
+
+func CheckNodes(nodes []SafeLine.Nodes, n int) []SafeLine.Nodes {
+	var need []SafeLine.Nodes
+	date := time.Now()
+	for _, node := range nodes {
+		days := int(node.ValidBefore.Sub(date).Hours() / 24)
+		if days <= n {
+			need = append(need, node)
+		}
+	}
+	return need
+}