Add accent insensitive query mode

Problem

Currently there is a possibility to search a database case insensitive with QueryMode.insensitive. I would like to additionally search the database accent insensitive.

Suggested solution

Extend the QueryMode.insensitive to be also accent insensitive or add the QueryMode.accentInsensitive with the possibility to combine the mode with QueryMode.insensitive (it would probably be good to rename QueryMode.insensitive to QueryMode.caseInsensitive)