Support stub functions

[benedeki]

Background

In proper (unit) tests, one wants to occasionally stub things for easier testing.

Feature

Add easy function stub creation.

Proposed Solution

Input:

• Function identification
  • function name including schema
  • list of input parameter types
• returned values - either a Seq of setters (for single row result) or Seq of Seq (when set of records is to be returned from the stub)