* Move all the initialization code out of `main.go`
* Ensure spans are reported when there's an error with the
command
* Attach the Compose version & active Docker context to the
resource instead of the span
* Name the root CLI span `cli/<cmd>` for clarity and grab
the full subcommand path (e.g. `alpha-viz` instead of just
`viz`)
Signed-off-by: Milas Bowman <milas.bowman@docker.com>