Add live-syncing from notebook to local machine

[nstogner]

Fixes #140

TODO: Arch description and diagrams.

[samos123]

This scenario might cause a user to lose their local changes:

1. In your local directory make some changes to the src/my-book.ipynb
2. Create a notebook that uses a prebuilt image
3. Use kubectl notebook to sync local directory

Assumption of what would happen, the notebook sync would sync the src/my-book.ipynb from the prebuilt image to my local directory. That would overwrite my local changes.

Workaround: Ensure only sync local directory can be used when building the image from local directory?

[nstogner]

@samos123 Agreed, that scenario could be an issue. A tricky one to figure out a solution for, but a good one to keep noodling on.

[samos123]

I don't think that scenario should block this PR. I can file a separate issue for tackling that scenario.

[nstogner]

NOTE: updates to goreleaser end up churning out a release that looks like: https://github.com/substratusai/substratus/releases/tag/v0.0.99

[brandonjbjelland]

🚀