Update to MV3. Use declarativeNetRequest to implement normal mode.

[ikimonogakari]

Hi, I really like this extension, since it can both controls the web page, and desktop app.

According to Chrome, MV2 extension will stop working soon. I updated the extension to follow MV3 standard.

• webRequest api is no longer usable. MV3 provides declarativeNetRequest with similar capabilities.
  • I tested and it worked, those headers are set in the request.
• Updated other APIs which have been deprecated in MV3.

Just for my curiosity, after I dig into the code, I still cannot understand how this extension can affect the desktop app. Do you have an idea why this worked?