Fix similarity algos return

[tomasonjo]

Similarity algos return directed networks.

Currently, the generated query looks like:

MATCH (from)-[rel:`SIMILAR_JACCARD`]-(to)
WHERE exists(rel.`score`)
RETURN from, to, rel.`score` AS similarity
ORDER BY similarity DESC
LIMIT toInteger($limit);

It would need to match a directed relationship, I am also wondering if it makes sense to add id(from) < id(to) to remove all duplicates from the table

I think all similarity algos behave the same, have to double check