Global configuration file

The VS Code extension already got the option to pass a default config file, if no config file is provided in the project itself. We could do the same in two ways:

1. we have the Unibeautify config file in the user root ~/.unibeautifyrc.json
2. we use the ~/.unibeautifrc.json file to set CLI options e.g.:

{
  "defaultConfig": "/Users/marvinheilemann/Documents/Configs/.unibeautifyrc.json"
}