`fluksio run` walked the working directory and imported every module in
it, which ran a research repository's analysis scripts before the run was
submitted. A flow's origin now records the file and module name that
declared it, and run/sweep import just that, under the same name so the
generated node bodies do not change. A flow with no record still walks,
now skipping what .gitignore covers.
Every code-defined flow reports `flow` changed once on its next sync,
since the origin gained two fields.