Add Preview when user configures a new entity

[dividor]

Is your feature request related to a problem? Please describe.
Entities are set up where the user provides a SQL snippet. It would be good to add ' LIMIT 5' to the end of this and execute on-the-fly and display the results. This would also allow the form to have a pick-list for ID field

Describe the solution you'd like
It would be good to add ' LIMIT 5' to the end of this and execute on-the-fly and display the results