WIP: Add Provider Icons Rails

What does this MR do?

The current Cluster Index View has the following code:

- if Feature.enabled?(:clusters_list_redesign)
      #js-clusters-list-app{ data: { endpoint: clusterable.index_path(format: :json) } }
    - else
      .clusters-table.js-clusters-list
        .gl-responsive-table-row.table-row-header{ role: "row" }
          .table-section.section-60{ role: "rowheader" }
            = s_("ClusterIntegration|Kubernetes cluster")
          .table-section.section-30{ role: "rowheader" }
            = s_("ClusterIntegration|Environment scope")
          .table-section.section-10{ role: "rowheader" }
        - @clusters.each do |cluster|
          = render "cluster", cluster: cluster.present(current_user: current_user)
      = paginate @clusters, theme: "gitlab"

Feature.enabled?(:clusters_list_redesign) is part of a refactor where we are moving the cluster list to JS and removing haml files.

Currently, the haml section includes a provider icon that is missing in the JS Files

This MR will

• Add the icon to the JS component
• Remove boostrap classes from the component
• Adds provider_type to API
• Update associated tests

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team