New Block Types: Core\SetContactProperty and Core\SetGroupMembership about flow-spec

[markboots]

@bzabos @seifertk, I ran into an interesting question when writing the spec for the Set Contact Property block:

Since all blocks have the standard ability to set contact properties via:

config {
   ...,
   set_contact_property: {
      property_key: <string>
      property_value: <Expression>
   }
}

Should the config for the SetContactProperty block be consistent (as immediately above), embedded within the set_contact_property object?

Or should it be like this:

config {
   property_key: string,
   property_value: expression
}

If like this, and it also obeys "standard" block rules of being able to set a contact property like all blocks do... Does that mean it can actually set 2 contact properties in one block? ie:

config {
   property_key: "gender",
   property_value: "female",
   set_contact_property: {
      property_key: "age",
      property_value: "35"
   }
}

What choice did we implement in the Flow Runner?