Change request: Provide templated variables

[jayheavner]

I'm using the the call service node and passing in dynamic values. I've been using function/change nodes to construct the parameter but I'm wondering if a change could be made so I could use a template. Here's an potential example where I'm setting a select.

{"input.modes", {{msg.payload}} }

It's not a huge deal but it would save the transformation node before the call service node.