feat: move web page to html

[chemwolf6922]

Why is this change made

Putting the webpage inside a string is not ideal for maintenance.

Changes

• Move the web page to a html file.
• Translate using miot i18n.

Tests

Tested login in my local environment.

[topsworld]

Test passed in my develop machine.

[SusanPhevos]

@chemwolf6922
Dear contributor,
Thanks for your contribution to ha_xiaomi_home. When you submitted your pull request, the Contributor License Agreement (CLA) of ha_xiaomi_home was not ready. We sincerely hope that you sign the CLA to ensure that all of your past and future contributions to ha_xiaomi_home are legally authorized.
Please view the CLA at https://cla-assistant.io/xiaomi/ha_xiaomi_home and click "Sign in with GitHub to agree" button to sign it.
Thanks again for your support!
ha_xiaomi_home Team

尊敬的开发者：
感谢您对 ha_xiaomi_home 开源项目的宝贵贡献！鉴于您提交 PR 时，项目的贡献者许可协议（Contributor License Agreement，CLA）尚未完善，我们希望您补签 CLA ，以确保您过往及未来对该项目的所有贡献均能被合法授权。
具体操作：请您在 https://cla-assistant.io/xiaomi/ha_xiaomi_home 中阅读 CLA 并点击“Sign in with GitHub to agree”按钮以签署协议。
再次感谢您的支持！
ha_xiaomi_home 团队

[chemwolf6922]

@chemwolf6922 Dear contributor, Thanks for your contribution to ha_xiaomi_home. When you submitted your pull request, the Contributor License Agreement (CLA) of ha_xiaomi_home was not ready. We sincerely hope that you sign the CLA to ensure that all of your past and future contributions to ha_xiaomi_home are legally authorized. Please view the CLA at https://cla-assistant.io/xiaomi/ha_xiaomi_home and click "Sign in with GitHub to agree" button to sign it. Thanks again for your support! ha_xiaomi_home Team

尊敬的开发者： 感谢您对 ha_xiaomi_home 开源项目的宝贵贡献！鉴于您提交 PR 时，项目的贡献者许可协议（Contributor License Agreement，CLA）尚未完善，我们希望您补签 CLA ，以确保您过往及未来对该项目的所有贡献均能被合法授权。 具体操作：请您在 https://cla-assistant.io/xiaomi/ha_xiaomi_home 中阅读 CLA 并点击“Sign in with GitHub to agree”按钮以签署协议。 再次感谢您的支持！ ha_xiaomi_home 团队

目前的CLA没有说明以下问题，我拒绝签署，请加以完善：

1. 请明确说明贡献者能和不能对“贡献”进行的操作，例如在什么情况下构成对小米的侵权。
2. 请说明社区贡献者的贡献将如何被体现。