Add a CLI command for retrieving the autopilot configuration.

[mkeeler]

This is a small shim around the new /v1/operator/autopilot/state endpoint. The new command supports both JSON and pretty output formats.

[schristoff]

Everything looks great, I hardly have any comments. Aside from the thing we discussed in Slack I think my only concern is that locally I am getting remnants of enterprise features in my output, however this is probably just be a me issue. Just wanted to bring it up in case it shows up.
I'm going to approve this now since there is only 1 small thing needed to be added and then it should be good.

[mkeeler]

The output contains 2 things that would look enterprise related. the first is the optimistic failure tolerance and the second is the network segment showing up in the server Meta.

The empty network segment meta is due to Consul OSS always populating that here:

consul/agent/agent.go

Line 3402 in 3760e3d

meta[structs.MetaSegmentKey] = conf.SegmentName

The optimistic failure tolerance which really only applies when redundancy zones are in use is due to the field in the api.AutopilotState struct being an int and that 0 is a valid value when the system cannot tolerate more failures. So we cannot just tag the field with a omitempty JSON tag. We could turn this field into a pointer in which case we could detect being unset vs a zero value but the ergonomics of using the struct would be diminished.

[hashicorp-ci]

🍒 Starting backport cherry picking.

To cherry-pick post-merge, add backport labels and re-run https://circleci.com/gh/hashicorp/consul/278550.

[hashicorp-ci]

🍒✅ Cherry pick of commit 7ef9b04 onto release/1.9.x succeeded!