Dvince/clean up workflows

[dvince2]

Description

This is a tentitive proposal for how to clean up workflows. Functionally this works however I'm not sure if its the "best" solution available and any feedback would be welcome. Basically...

• In the workflow table, we check the nodes and edges columns which are json arrays, and collect any workflows which have a node and an edge marked for deletion
• These workflows are returned in a set as there may be some overlap between the two collections.
• In Java we remove the edges and nodes from their lists inside of the workflow
• The workflows are all saved.

Is it possible to find both nodes and edges at once in a single call or will it always be two?

[bigglesandginger]

I think this is a "best of both worlds" approach. It is clear, the SQL is easy to read, and the Java leverages the existing knowledge space. Could it be faster all in PostGres... maybe but for not much of a gain.

[mwdchang]

Didn't test, but code seems okay