v5.1.0

Version 5.1.0

• Added new todo.archive.type setting — controls where archived todos are stored: in the same file, in a single workspace-level archive file, or in
  per-file archive files (default: InMultiSeparateFile).
• Removed todo.indentation in favour of automatic detection based on vscode settings.
• Improved archiving by preserving projects structure and merging tasks into already existing archived projects, #32
• Added unit tests