add contains function for conditional/filtering of smart value lists

As an automation rule writer
I want to test if a list contains a value within smart value/conditional filtering
So specific items within a source list can be processed

Acceptance criteria:

• the contains() function is added for list processing
• contains() has a parameter for the value to find
• when the value is found the result is true, and is false (null) otherwise
• when the tested list is null, the result of contains() is always false (null)
• Bonus: the parameter can optionally be a list of values to test; leading to an intersection test of the sets of the source list and parameter

Usage scenario:

Lists can be examined using regular expression matches or conditional filtering.  Yet when the source list contains child lists, it is not easily testable for the contents of that child list.  The values can be extracted and tested using regular expression matches, but then the parent object is not available: only the matching values.  Think of a Lookup Issues result of issues, containing a list of sprint values in each.  One possible work-around today is to try to use the JQL and repeated calls to Lookup Issues.  Having the ability to perform contains() tests on the child lists enables using just one Lookup Issues call, followed by filtering the data as needed.