This endpoint is relatively expensive, as it returns a large amount of
data for each stack (essentially the stack's entire checkpoint). We
currently call this endpoint in a few places that really just need
information about a single stack. In these places we should simply
interact with that stack directly.
After these changes, there is only one call to the `stacks` endpoint on
the startup path: `upgradeConfigurationFiles` loops over all of the
stacks in each backend and attempts to upgrade each stack's
configuration. Once we no longer need to do this we will not be hitting
the `stacks` endpoint on each CLI invocation.