Introduce operating system package field

[AMDmi3]

https://repology.org/project/wire/information: wire has different versioning schemes dependent on OS, there are more examples in 902 ruleset. We don't have enough information to split cases like this, as homepage is usually the same for different OSes. We can, however, infer this information from repository. There are OS-specific repos for which OS can be defined in repository config, and there are cross-platform repositories for which OS can usually be determined during parsing. We can add a corresponding field, fill it as described, and use it to split projects by OS.