Reduce ODRS plugin allocations
See commit messages.
tl;dr: This saves 1MB of heap memory and over 4000 allocations (given the current number of 4113 entries in ratings.json
, as per https://gitlab.gnome.org/pwithnall/gnome-software/-/merge_requests/new?merge_request%5Bsource_branch%5D=odrs-allocations
), at the cost of slightly slower lookups of ODRS data.