[UII] Suggest content packages based on discovery property

[jen-huang]

Related to #192484
Related to elastic/package-spec#351

In the above issues we added support for content packages. This package type introduces a discovery mechanism based on the data the package can work with. For example the following definition would indicate that the package provides resources that are useful when used with data that includes the field process.pid:

discovery:
  fields:
    - name: "process.pid"

The package registry supports searching for packages that have support for certain fields. For example a request like the following one could be used to discover packages that include resources that can leverage the process.pid or the user.id fields.

GET /search?discovery=fields:process.pid,user.id

(source: elastic/package-spec#777, elastic/package-registry#1229)

We should leverage this feature to recommend relevant content packages for the user to install. There are a couple of ways the UX could happen:

• On an installed integration details page, show a callout with recommended content packages based on the fields defined in that integration

• Add a Recommended integrations tab to Integrations browse page. For now this will list content packages based on all other packages the user has installed, in the future we can leverage this area to suggest integrations based on user's ingested data. This could look something like this:

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)