Platform API for static HTML page rendering

[mshustov]

Currently, the platform doesn't expose rendering_service API to plugins. Instead, we recommend plugins leverage the http_resources service that provides methods to register a custom endpoint for HTML page rendering. Now we have a use-case when a page should be rendered outside of the request handler: #75538
The platform should provide API allowing a plugin to render a page in any lifecycle stage, including http-request interceptor.
Blocked by #54375, since we want to provide the ability to render a static HTML page with Kibana CSS styles.

[elasticmachine]

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

[pgayvallet]

Given that:

• Give user the option to log out if they encounter a 403 #75538 was addressed by working around this limitation
• we never received any (serious) further requests of such "react server-side render service"
• this is far from trivial, and coupled to low level / build components such as the optimizer

I'll consider we're not planning on doing this and will close the issue.