fixes bug with build process on subdirectories in templates/ folder

*Example scenario*

```
// Folder structure
+ templates/rosy/base.html
+ templates/rosy/index.html
```

Running `statix:build` results in error on Line 202 of statix-cli.js when moving `index.html` into the folder `rosy` that does not exist in the deploy folder.

This PR fixes that issue by ensure the directory exists before copying the files over.