Stop "indo" command from creating .indo.json when one does not exist

The `indo` command is useful even in repos that have no reason to keep a `.indo.json` file in version control. For example, after an npm client runs an `install` command, `indo` can re-link packages that were previously added with `indo link`.

Only commands like `indo clone` and `indo share` should create a `.indo.json` file on-demand.