Add gradio admin interface
A simple Gradio app to show the pending jobs.

Contrary to the observable notebook, this can run locally and connect to your local dev environment.

I added a feature to see the number of jobs in the queue, and a simple SQL query feature that uses DuckDB.

The app can be extended to support more admin features e.g.
- refresh jobs
- cancel jobs
- show report

I'll also deploy it on Spaces

![image](https://user-images.githubusercontent.com/42851186/215569915-3fe18176-3e21-433e-bfb0-af6a7eef137e.png)

Add gradio admin interface: A simple Gradio app to show the pending jobs.

Contrary to the observable notebook, this can run locally and connect to your local dev environment.

I added a feature to see the number of jobs in the queue, and a simple SQL query feature that uses DuckDB.

The app can be extended to support more admin features e.g.
- refresh jobs
- cancel jobs
- show report

I'll also deploy it on Spaces

![image](https://user-images.githubusercontent.com/42851186/215569915-3fe18176-3e21-433e-bfb0-af6a7eef137e.png)
