Search has unclear and unpredictable behaviour

It is not clear to end-users how to properly use the search. For example, for some users it is intuitive to, based on the displayed guide when searching, do something like `person: John Doe`. However, this will not search John Doe and instead will search on 'John' and 'Doe'.

The solution would be to type either `person:"John Doe"` or 'person:John Doe` (no space).

On top of that, we do support `AND` and `OR` operators in the search as we simply pass the search string to elastic, but this is not stated anywhere. There is no highlighting of search keywords or feedback when using it wrong.

**Solution**
Some way to highlight the search keywords, or make it clear that it is being used incorrectly. Also mention of the AND/OR operators and how this works, either implicitly with highlighting or explicitly in the guide directly below.