Options for selecting the authuser and hl parameters

[tueda]

It would be useful if the extension could append custom query parameters like authuser and hl to the generated Colab links.

Example use cases:

• authuser=1: to open using the second Google account (I use a second account for work/teaching)
• hl=en: to force the UI to be in English

As an alternative to supporting them individually, it might be simpler to let users specify an arbitrary query string in the settings (e.g., authuser=1&hl=en).

The default behaviour would remain unchanged (no query string is appended) if no query string is set.

[peap]

Thanks for the request! Tracking internally as b/459892694.