Decouple Obsidian

[Seb-stian]

Obsidian is a large project that consists of many parts. At the moment, everything sort of melts together, which is bad for maintainability and extensibility.

• [x] Separate console front-end to a new project
  • [ ] Make sure that we only have things public when they should be
  • [ ] Make types sealed as appropriate
• [x] Move Obsidian.ConversionUtility to repository Tools
• [x] Move Obsidian/scripts to repository Tools
• [ ] Move Obsidian.Nbt to its own repository
• [ ] Rethink project folder/namespace structure (?)

Some tasks (?) need further discussing.