Support interpolation for group services

[tgross]

Task services are interpolated with the task environment (the env vars plus information about the node) prior to being registered with Consul and prior to starting their checks. In 0.10.0 we're interpolate the task environment for task group script checks but not the task group services or non-script checks, because only script checks take place in the context of a task.

We should be able to support interpolation for task group services with the node and alloc information at least.

[github-actions]

I'm going to lock this issue because it has been closed for 120 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.