Make publish command aware of uploads directory

[bgins]

NB: Feature requests will only be considered if they solve a pain

Summary

Problem

If a developer appends to an app, then publishes the app, their appended files will no longer be available in the app.

Impact

Confusing developer experience. A developer will not expect their uploads to disappear when they publish.

Solution

Make the publish command aware of the uploads directory to preserve it.

As a rough sketch:

• Check if uploads exists and get the CID for it
• Get a root CID for the app as published by the CLI
• Stitch the uploads directory back into the app
• Complete the publish and return the CID of the app with uploads put back in

There are likely more details to consider. For example, what happens when an app has an uploads directory locally.

[expede]

@bgins we should talk about this in more detail. I actually think that this breaks user expectation.