Add id field to entity definition

[dividor]

Is your feature request related to a problem? Please describe.
It was encountered when configuring for a partner who had tables that didn't include one of the hard-coded id names ("uuid", "reporter", etc)

Describe the solution you'd like
We should make providing an ID field mandatory, with a chooser of the columns returned by entity SQL. The UI could run the SQL with LIMIT 1 to see what results are returned