carlo: implied command dependencies

Given build options (cargo workspace options, e.g. `-p my_crate`), the
`upload` command will build before uploading, and given build or upload
options `create` will build or upload before creating a machine.

These primary options are mutually exclusive, but may require nested
ArgGroups in the future which are supposed to be supported, perhaps
aided by clap-rs/clap#2621 if resolved. The current constraints and
reuse of shared options is rather crude (see in particular
UploadOptsWrapper).