Add new theme color

[NeverEllipsis]

这个 PR 做了什么?
Add a new theme color, which we call the Pioneer-Theme. This theme is still being rapidly iterated and upgraded and is currently in an unstable state.

这个变动的性质是？

• 新特性提交
• 日常 bug 修复
• 站点、文档改进
• 演示代码改进
• 组件样式/交互改进
• TypeScript 定义更新
• 包体积优化
• 性能优化
• 功能增强
• 重构
• 代码风格优化
• 测试用例
• 工作流程

这个变动涉及以下渠道:

• 所有渠道
• 微信小程序
• 支付宝小程序
• 抖音小程序
• Web 平台（H5）

附加信息（可选）
在此添加任何其他相关信息，比如截图或设计图。

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 3 committers have signed the CLA.

✅ honghui-qiao
✅ NeverEllipsis
❌ wushuxuan
_{You have signed the CLA already but the status is still pending? Let us recheck it.}