uniapp字符串转base64，无需导入依赖（多端支持）

使用示例

import { Base64Encode, Base64Decode } from "@/utils/base64.js"

base64.js

const _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
export const Base64Encode = (text)