Apparently `dot` has a long lasting bug (recently fixed) which is the
root of the non-determinism:

https://gitlab.com/graphviz/graphviz/-/issues/2510

Test failed, not merging.

This reverts commit 2e77bfa5, reversing
changes made to fe201115.

This commit modifies the backend code to convert the input CSV into an
`NgramsList`, so that we can reuse the JSON API for the upload.

it also brings the CSV and JSON APIs closer in look.
Temporarily disable the `importCsvFile` function.

We now require CoreNLP listening on port :9000. We will have to find
a way to spin that up in CI as well.

This commit fixes a bug (or feature? unclear at this stage) of the
`rootOf` function inside `searchTableNgrams`, which could, in some
occasion, return a root which has a different `ListType`, which
in turn throws off pagination.