Add default role to workspace (#10444)

## Context
Adding a defaultRole to each workspace, this role will be automatically
added when a member joins a workspace via invite link or public link
(seeds work differently though).
Took the occasion to refactor a bit the frontend components, splitting
them in smaller components for more readability.

## Test
<img width="948" alt="Screenshot 2025-02-24 at 14 54 02"
src="https://github.com/user-attachments/assets/13ef1452-d3c9-4385-940c-2ced0f0b05ef"
/>

packages/twenty-front/src/modules/workspace/graphql/mutations/updateWorkspace.ts

@@ -1,6 +1,8 @@
+import { ROLE_FRAGMENT } from '@/settings/roles/graphql/fragments/roleFragment';
 import { gql } from '@apollo/client';
 
 export const UPDATE_WORKSPACE = gql`
+  ${ROLE_FRAGMENT}
   mutation UpdateWorkspace($input: UpdateWorkspaceInput!) {
     updateWorkspace(data: $input) {
       id
@@ -13,6 +15,9 @@ export const UPDATE_WORKSPACE = gql`
       isGoogleAuthEnabled
       isMicrosoftAuthEnabled
       isPasswordAuthEnabled
+      defaultRole {
+        ...RoleFragment
+      }
     }
   }
 `;