[TOOLING] sql queries to remove unused documents and ngrams from database. Usage: use a crontab to execute it every week for instance.

Also, add "Advanced" endpoint for node list update to update charts.

This is not the optimal solution since it duplicates so much
data. Best would be to add "children" in the node directly.

Dev doc create endpoint

See merge request !64

Merge branch '81-dev-zip-upload' of ssh://gitlab.iscpif.fr:20022/gargantext/haskell-gargantext into dev-merge

This is because to_tsquery doesn't work with multiple words not
separated by AND or OR.