Features:
- meson
- (almost) all strings are localized
- relm4_icons no longer used
- default.nix updated but not tested
- updated dependencies
- unused for now: paket-utils, paket/locker
- build-aux/checks.sh now enforced
- fixups in libpaket/tracking parsing
- libpaket: RegTokenDecodeError instead of generic DecodeError
- moving dependency versions to workspace Cargo.toml
- default.nix adjusted
- README.md added
- dependency: relm4 version pinned to include fixes
