Display and "save" the base image a notebook uses in a notebook cell

[WillEngler]

We have a little first draft system for pairing a notebook with a base image that looks like this ...

1. User says garden-ai notebook start foo.ipynb --base-image=3.10-torch
2. We save a mapping from current/directory/foo.ipynb to 3.10-torch in the user's local data
3. Then the user can say garden-ai notebook start foo.ipynb and we open up it up again in the right image.

This is nice as a quick first pass but ofc it's pretty fragile. If the user mvs the notebook to a different directory they'll be prompted again to specify the base image.

I suggest that when making a new notebook from a template we create a first cell that presents (in a nice user-readable format) what base image this notebook uses. If the user decides to change it later, that is well and good! They can just edit the cell.

This has a few benefits

• We don't need a local DB mapping anymore
• The user can move the notebook around or even send it to another machine and the notebook keeps its own metadata. (Especially useful if we're debugging someone else's notebook)

Assumptions:

1. 5.

Acceptance Criteria

Given..., when..., then...

[WillEngler]

Now that we let users specify a --requirements file, that's something we can also think about in this ticket. The base image we provide and the requirements a user has specified feel pretty linked in the user's mind. So we'll want to think about those holistically.