Convert XML files to JSON

[ekolis]

Describe the feature you'd like to see
All mod files, savegames, etc. should be stored as JSON instead of XML.

Benefits
JSON is easier to read and write than XML due to the lack of close tags. We can use JSON.NET to serialize/deserialize data without having to work with XmlDocuments and such.

Describe alternatives
YAML maybe? I dunno...

Additional context
One concern I have is that JSON is not quite as well supported when it comes to tooling as XML, perhaps because XML I think is older.