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-server/src/engine/metadata-modules/role/role.service.ts

@@ -21,6 +21,19 @@ export class RoleService {
     });
   }
 
+  public async getRoleById(
+    id: string,
+    workspaceId: string,
+  ): Promise<RoleEntity | null> {
+    return this.roleRepository.findOne({
+      where: {
+        id,
+        workspaceId,
+      },
+      relations: ['userWorkspaceRoles'],
+    });
+  }
+
   public async createAdminRole({
     workspaceId,
   }: {