feta: add hosts support domain and mulitple ip (#439)

* feat: host support domain and multiple ips

* chore: append local address via `clash`

* chore: update hosts demo

* chore: unified parse mixed string and array

* fix: flatten cname

* chore: adjust logic

* chore: reuse code

* chore: use cname in tunnel

* chore: try use domain mapping when normal dns

* chore: format code

common/utils/slice.go

@@ -0,0 +1,34 @@
+package utils
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+func Filter[T comparable](tSlice []T, filter func(t T) bool) []T {
+	result := make([]T, 0)
+	for _, t := range tSlice {
+		if filter(t) {
+			result = append(result, t)
+		}
+	}
+	return result
+}
+
+func ToStringSlice(value any) ([]string, error) {
+	strArr := make([]string, 0)
+	switch reflect.TypeOf(value).Kind() {
+	case reflect.Slice, reflect.Array:
+		origin := reflect.ValueOf(value)
+		for i := 0; i < origin.Len(); i++ {
+			item := fmt.Sprintf("%v", origin.Index(i))
+			strArr = append(strArr, item)
+		}
+	case reflect.String:
+		strArr = append(strArr, fmt.Sprintf("%v", value))
+	default:
+		return nil, errors.New("value format error, must be string or array")
+	}
+	return strArr, nil
+}