Alternative version matchers

[Lonami]

Split off #206. Currently a "release info" can only match on a specific version names:

https://github.com/DarkEld3r/os_info/blob/f9088845198fa9951f6d97a7bb35d035046f707b/os_info/src/linux/file_release.rs#L72-L76

However, the same file may be used by different operative systems. Not only will os_type be wrong (it can just be a guess), but other systems may use different key names. In the case of Arch Linux, the version is in BUILD_ID, not VERSION_ID.

This issue is here to discuss the best way to handle stuff like this.