Explore and re-evaluate how grails-shell Scripts are provided to the application

### Issue description

There are many grails-shell Scripts commonly used while generating, maintaining and executing a Grails application. They are currently provided by profiles and plugins (default and non-default).

Some scripts are dependent on the plugin, where others are entirely standalone. Explore the best location for each script to live and how it is provided to the end application.

Start by inventorying the grails-shell scripts currently provided by default and non-default profiles and plugins. Compare which scripts depend on their providing plugin versus which are standalone; done means the best location and delivery method for each script has been evaluated and documented.

Written by the indexing model from the issue text.