Add component info to BRP registry schema

[splo]

Objective

Add component metadata to the BRP registry.schema method.

The following data related to components is missing and this PR adds it:

• Whether the component is mutable or not.
• Type paths of required components.
• Whether the component is a relationship or relationship target.

Other metadata could easily be added, basically everything in the ComponentInfo type.

Solution

• Once per type, use World::components to obtain an eventual ComponentId and ComponentInfo.
• Use it to fill the new component_info field.
• It doesn't introduce a breaking change, as the new field is optional and hidden for non-component types.

Testing

• I added a unit test. It verifies mutability, required components, and relationship kind for a few test components.
• I also called BRP to retrieve a schema and verify the returned data is correct.

---

Showcase

Here are a few example of the returned JSON schema when calling the BRP registry.schema method:

{
"bevy_ecs::hierarchy::ChildOf": {
  "componentInfo": {
    "mutable": false,
    "relationshipKind": "Relationship"
  },
  // Other fields hidden for brevity.
},
"bevy_ecs::hierarchy::Children": {
  "componentInfo": {
    "mutable": true,
    "relationshipKind": "RelationshipTarget"
  },
  // Other fields hidden for brevity.
},
"bevy_transform::components::transform::Transform": {
  "componentInfo": {
    "mutable": true,
    "requiredComponentTypes": [
      "bevy_transform::components::global_transform::GlobalTransform",
      "bevy_transform::components::transform::TransformTreeChanged"
    ]
  },
  // Other fields hidden for brevity.
}

[splo]

This PR relates to issue #23076 but it doesn't fix it: this PR adds the missing component info to BRP while the issue is about adding it to reflect.