[Infra + Logs UI] Provide cross-app link functions

[jasonrhodes]

To make linking between solutions easier/less brittle, we've decided to try an idea where each app provides its own "linking functions" that other apps will use when they want to link into an app.

A link function should do the following things:

• Accept any number of typed arguments (e.g. a time range, a list of metrics, a trace ID, etc.)
• Return an object with the following shape:

{
  status: "enabled" | "disabled"; // (others? if we only need two states we could switch to enabled: boolean;)
  href: string;
}

• Be defined in x-pack/legacy/plugins/observability/public/link_functions/{your_app}/*
• Be exported from x-pack/legacy/plugins/observability/public/index.ts
• Handle license, permissions, feature controls, and enabled/disabled state internally
  • If this calculation requires core plugin services (e.g. uiCapabilities, current license info, etc), they need to be passed in (observability plugin is static only right now: maybe we should make it a "real" plugin so it can consume its own services?)
  • If the calculation determines that the link can't be generated, it should return the appropriate status (still need to determine how much information we need to give the caller about this, if there's a difference between invalid license or feature control disabled etc.)

Consider providing a shared React component that renders null if the passed in link function returns an invalid state, or calls children with the href value if the state is valid, to make it easier to hide invalid links?

[elasticmachine]

Pinging @elastic/infra-logs-ui

[alvarolobato]

@sgrodzicki @jasonrhodes we found another bug on the linking between apps (#41568) I think this needs to be prioritized, in fact, I thought Jason was actively working on this, I must have miss-understood.
Moving this back to inbox for re-triage and know what the team thinks about re-prioritizing.

[jasonrhodes]

@alvarolobato thanks, the work I did was to get to the point of being able to create this ticket to implement :) this is one of the highest priority tech-debt/internal improvements we have -- I was waiting for feature work to get off the ground before we pull this into grooming.

[sgrodzicki]

@jasonrhodes what's the current state of this?

[simianhacker]

Re-open if this is still valid