Make time range variables $end and $start available for in grafana templating variables

[ghost]

Use case: I want to create a templating variable 'active_issue' to allow the user to select an issue among the list of ACTIVE issues during the selected time range.

Problem: the time range selected - $start and $end variables that I can use in a panel - is unknown in the templating variable space. I can only select active issues NOW and not ofr the selected time range.

Request: make those variables available for templating variables.