Adapt status page UI to 8.0 /api/status format

[joshdover]

#76054 introduces a query parameter to use a new format for the /api/status endpoint that drops many of the legacy concepts and fields. The Status Page UI code in core needs to be adjusted to use this new API format before 8.0.

We could also use this opportunity to split out Core service statuses from plugin statuses in the UI.

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[pgayvallet]

Should we move this issue to our 7.12 or 7.13 roadmap?

[joshdover]

Blocks #94419

[thesmallestduck]

I had a chat with @ryankeairns briefly. There's no objections to simply suppressing core plugin status or splitting the plugin status list into sections as we see fit. If we decide we want to do something more fancy with the UI we can loop in kibana-design formally and get some wireframes and what not.

[ryankeairns]

+1 and if you'd like feedback on this initial PR (or any for that matter), just mention us with @ kibana-design

[afharo]

We agreed to scope this issue only to adapt the current design to the new output of the /api/status format.

To discuss about any redesign of the page, I've created #107873