Break score ties in patient search results

[make-github-pseudonymous-again]

Currently sorted order of results can change if their score is the same. Then pagination is difficult to work with because an item could appear on different pages with the same text query and database state. This can happen for instance when going from page 1 to page 2 of the results. To make this predictable we need to use a compound index to break ties. Maybe {...textIndexFields, lastname: 1, firstname: 1, niss: 1, birthdate: 1}. See https://docs.mongodb.com/manual/core/index-text/#std-label-text-index-compound and https://stackoverflow.com/questions/31652975/mongodb-how-to-do-a-text-search-and-sort-by-a-date.

[make-github-pseudonymous-again]

Or {...textIndexFields, lastModifiedAt: -1, lastname: 1, firstname: 1, niss: 1, birthdate: 1}.