Fix highlighting in query results

[vanatteveldt]

Current system is a bit of a mess with

• highlight param is either dict or bool
• highlighting has an unclear relation with annotations

Solution:

• drop all annotations
• highlight as enum {none, highlights, snippets} , of highlight={type: [enum], ...}

[vanatteveldt]

@kasperwelbers I think you implemented this, correct?

[kasperwelbers]

I think I did. Internally it might still look complicated because the elastic highlight mechanic is related to the snippet mechanic. But I think its now robust, and no longer confusing in our api.

So if you agree with the solution we can close this