feat: add replay protection plugin (#1672)

Co-authored-by: hanxiantao <601803023@qq.com>

plugins/wasm-go/extensions/replay-protection/util/utils.go

@@ -0,0 +1,8 @@
+package util
+
+import re "github.com/wasilibs/go-re2"
+
+// IsValidBase64 checks if a string is a valid base64 encoded string
+func IsValidBase64(s string) bool {
+	return re.MustCompile(`^[a-zA-Z0-9+/=-]+$`).MatchString(s)
+}