Mods updates system

[BadRyuner]

During the loading of mods checks for updates for the mod, if the developer has provided a link to a special link.
Also allows you to update the mod with the click of a button. Unfortunately, the changes will only apply after restarting the game.

Special file: https://github.com/BadRyuner/PulsarBotIntegration/blob/master/Version.json
How to provide: https://github.com/BadRyuner/PulsarBotIntegration/blob/master/Mod.cs#L27

How it looks in the game:

(!) - means this mod is outdated.

To indicate a new version, the modder only needs to update his Version.json on the master branch of the mod by changing Version and DownloadLink.

[Nagord]

Took a quick skim, everything looks fine.

The old ModID string should have been marked obsolete for cases where devs added it, but it shouldn't have been implemented by anyone yet.

Additionally, it looks like the updater might crash if the expected information isn't found (mod.VersionLink points to the wrong location, file.Version doesn't exist). This crash is dependent on JsonConvert.DeserializeObject returning a VersionFile object with empty strings or simply crashing if the expected values aren't found. I haven't tested at this time, but if these are issues we'll deal with them in upcoming commits.