Add option to favourite food database entries and/or to sort by frequency of usage

[drunken-dwarf]

In addition to #18 I would like to be able to favourite food database entries and/or have them sorted by usage.
The information about how many times a certain entry has been used is already present.

Since there are a lot of duplicates coming from the different sources, which sometimes also have different or plainly wrong values, I'd like to be able to favourite the entries I deem correct.

[Faltenreich]

This is a really good idea and should be feasible as the required data is already available, as you mentioned. I am currently working on a major release which overhauls the food list as well, and this request could be implement as a sorting feature in addition to the list being sorted alphabetically by default.