[cache] Rename cache copy, add single package functionality

[mikeland73]

Summary

Renames devbox cache copy to devbox cache upload. Also changes the interface to use --to flag for cache URI. This allows easier use if cache is provided by jetpack API.

e.g.

# upload project packages to jetpack provided cache
devbox cache upload

# upload installable to jetpack provided cache
devbox cache upload <installable>

If user wishes to specify cache URI, they can do:

# upload project
devbox cache upload --to 's3://mike-test-nix-cache?region=us-west-2'

# upload single installable
devbox cache upload --to 's3://mike-test-nix-cache?region=us-west-2' nixpkgs#php

How was it tested?

devbox cache upload --to 's3://mike-test-nix-cache?region=us-west-2'
devbox cache upload --to 's3://mike-test-nix-cache?region=us-west-2' nixpkgs#php

Inspected cache on aws.

[savil]

I don't follow this description at all!

[savil]

upload specified nix installable or nix packages in current project to cache

[mikeland73]

Will improve