feat(vscode): allow quickly opening a route in the browser

[alestiago]

Description

To have an additional Command and Code Lens provider that allows quickly opening a route in the browser.

Requirements

• [ ] Remove automatically opening a server in the browser when starting a development server.
• [ ] Introduce a new "Open" Code Lens provider on route handlers (eg, "Run" | "Debug" | "Open").
• [ ] Introduce a new command "Dart Frog: Open in browser" that will open a route in the browser. If there are no running servers, it will start one.
• [ ] Introduce an icon in the debug toolbar to quickly open relative to active route
• [ ] Update status icon to quickly open relative to active route

Additional Context

• https://github.com/VeryGoodOpenSource/dart_frog/pull/991