Dynamically download new anime relations

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Anime relations seems to release new changes more often than Tundra does its releases (which contain those updates). It would be beneficial for Tundra to be able to grab those changes (on start, on user request, etc.) during runtime, not only during compilation during installation/update.

This has the apparent minus of requiring an Internet connection to grab that file during installation/update instead of being included in the binary, but the Internet connection is required for it, nevertheless.

The significant advantage is that the users will always have the newest relations available to them, no matter the Tundra version.