[Feature controls] Allow Elasticsearch features to be hidden in individual spaces

[legrego]

Summary

We manage two types of features today: Kibana Features and Elasticsearch Features.

Kibana Features are those which respect the Kibana Privilege model -- a vast majority of our features are considered Kibana Features. These features can be disabled at the space level, and access can be managed via Kibana's RBAC model.

Elasticsearch Features are those which rely on cluster and/or index privileges in order to function. Broadly speaking, most Stack Management apps fall into this category. For example, Index Lifecycle Management requires the manage_ilm cluster privilege in order to function. They were introduced in #67791, which gave us the ability to hide stack management features based on cluster/index privileges.

These features CANNOT be disabled at the space level. If an administrator wants to hide an Elasticsearch feature, they must either configure their roles to forbid access, or disable the plugins via kibana.yml.

#89584 prevents us from disabling plugins by default starting in 8.0, so there is a desire to allow Elasticsearch Features to be disabled at the space level. Note that this does not impact the privilege model at all. This is merely an update to the UI-based space level controls.

Tasks

Update the Elasticsearch Feature model

The ElasticsearchFeature model will need to be updated to include:

1. name
2. category
3. order
4. an option to indicate if they should be included for Spaces management. Opting in makes name, category, and order required. Otherwise they should not be specified.

  /**
   * Display name for this feature.
   * This will be displayed to end-users, so a translatable string is advised for i18n.
   */
  name?: string;

  /**
   * The category for this feature.
   * This will be used to organize the list of features for display within the
   * Spaces management screen.
   */
  category?: AppCategory;

  /**
   * An ordinal used to sort features relative to one another for display.
   */
  order?: number;

The associated validation schema will also need to be updated.

Update the Spaces capability switcher

The Spaces capability switcher will need to be updated to respect Elasticsearch Features that wish to be visible in the spaces management screen.

Update the Spaces management UI

The management UI will need to be updated to show Elasticsearch Features that have opted into per-space control.

cc @sebelga @cjcenizal

[elasticmachine]

Pinging @elastic/kibana-security (Team:Security)

[kunisen]

Should we also expand this concept to "Index privileges"?

Currently, the index privilege is defined as ALL spaces wide.

It would be great if we could define the index privilege per space.

[legrego]

Should we also expand this concept to "Index privileges"?

Currently, the index privilege is defined as ALL spaces wide.

It would be great if we could define the index privilege per space.

@kunisen I view that as a separate feature request. There is another issue or comment asking for something very similar, but I'm struggling to find it right now