Explore options to implement sqlite-based FTS (full text search) in order to replace haystack

[saemideluxe]

haystack is nice, but maintenance is not ensured. Also, haystack can do much more than what we require for bread. I suggest, in order to simplify the stack and reduce dependencies, that we take a look at if and how sqlite FTS could be implemented for bread, inside Python/Django, with minimal overhead and a simple API.