Rework "open in browser" modal

[colejd]

When you press the button to open a link in a web browser, you get three options:

• Open in Chrome
• Open in default app
• Share URL

Instead of assuming Chrome, we should make the first option configurable, so it'd be more like this:

• Open in [configured external browser]
• Open in default app
• Share URL

We should also guarantee that the first option doesn't open universal links in a native app. This is easy to verify with basically any link to a product on Amazon.