Epic: Add support for multiple active gateways

[raffaelespazzoli]

multiple active gateways can increase the bandwidth. Some cloud provider have limited instance-to-instance bandwidth between regions, so this feature is an enabler for all throughput-sensitive workloads.

Enhancement document: #69

[dfarrell07]

@Billy99 mentioned the Axon team might be taking a look at this.

[Billy99]

Enhancement document: #69

[dfarrell07]

Talking about this on the PR scrub today:

• It seems like the EP and feature branch are quite ready for non-globalnet, but GN would require lots more code changes, more design thinking.
• Tom pointed out that the GN code change would be good refactoring anyway, lot of code dupe to be fixed, separation of concerns, other refactoring that would be generally helpful.
• Are there smaller parts (like refactoring GN) we can go ahead and get merged to devel, to pave the way for this later?

Can we go ahead and raise small tasks to track some of these smaller chunks, so we can go ahead and work on them this release (without expecting the full Epic/EP to be finished)? We can triage these tasks' prio on the Scrub and they would be okay to work on this release.