Turn labelanalysis and staticanalysis views into noops

As part of deprecating ATS, this turns all the views into noops that return empty objects.

Checking in with the requests that the CLI sends, returning an empty `external_id` and `absent_labels` for the labelanalysis will result in the CLI falling back to using the clientside requested labels.

Similarly, returning an empty list of `filepaths` means that the CLI will not do any further uploads.

Author: Swatinem