Determine and produce structured question formulator output

[nsbgn]

As mentioned in #1, we need to get rid of the overlap between the grammar and the Blockly interface.

For this, the blocks should generate not another semi-natural language question that needs to pass through the whole parsing pipeline again, but rather, a structure from which functional roles are derived directly.

For example, the machine learning libraries that were used to recognize entities should be removed in favour of constraining the blocks in such a way that we already know the entity types. This will speed up the process and simplify the environment.

What other information should be conveyed by the block's output to be able to recognize functional roles? That should inform the details of the structure.

Once we have a better idea of what that structure should look like, we can generate it from blocks; see this page for more information.