Add customer relations organizations viewer

What does this MR do and why?

We recently introduced the root component as a placeholder. This MR now wires it up to display a list of crm organizations.

Screenshots or screen recordings

How to set up and validate locally

1. Enable feature flag:
Feature.enable(:customer_relations)
2. Pick a group (I used flightjs) and create some organizations (either via graphiql or rails console):
mutation {
  customerRelationsOrganizationCreate(input:
    { 
      groupId: "gid://gitlab/Group/26" 
      name: "ABC Company Ltd"
      defaultRate: 123
      description: "VIP"
    }) {
    organization {
      id
      name
      defaultRate
      description
    }
    errors
  }
}

3. Navigate to the organizations page: http://gdk.test:3000/groups/flightjs/-/crm/organizations (left hand nav menu from the group, "Customer relations -> Organizations")

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #2256