Make external address usage configurable
What does this MR do?
Fixes: #29556 (closed)
Makes autoscaler's UseExternalAddr configurable from Runner's config.toml.
Why was this MR needed?
Users may want to use internal networking to communicate Runner with instances while still have external addresses attached to them. This is needed, for example, to allow instances to talk with public Internet in some of the cloud providers (unless a more complicated setup with dedicated NAT router is introduced). This is for example needed for our upcoming MacOS SaaS Runners based on AWS.
Currently UseExternalAddr was hardcoded to true and internal address was used only if the external one was not available. With this change expected behavior can be configured through config.toml.
What's the best way to test this MR?
What are the relevant issue numbers?
Edited by Nick Klick