We have contexts.hash_id which is enough (computed by postgres as a
trigger).

When user searched for a phrase with space inside, in database, the
'to_tsquery' function raised an sql error. One should use
'plainto_tsquery'. Also, a proper test was added.

- DBCmd instead of Cmd
- remove FlowCmdM in favor of HasNodeStory

Tests were written with a very flat module hierarchy which made them
a bit confusing to navigate. This commit moves everything under a common
`Test.*` hierarchy.

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