Add `tunnel` option (sets the url used by transport)

### Description

Sets the URL that will be used to transport captured events. This can be used to work around ad-blockers or to have more granular control over events sent to Sentry.

- More details about the option in JS docs https://docs.sentry.io/platforms/javascript/configuration/options
- Related RN issue https://github.com/getsentry/sentry-react-native/issues/3258
- Related Cocoa issue https://github.com/getsentry/sentry-cocoa/issues/3583

先將要求的選項與 Java SDK 的傳輸設定以及連結的 JavaScript 選項文件進行比較。當新的 `tunnel` 選項控制用來傳輸擷取事件的 URL 時，即表示完成；issue 中未指定任何檔案或測試路徑。

由索引模型根據 Issue 內容生成。