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/users/components/UserProviderEffect.tsx

@@ -57,7 +57,10 @@ export const UserProviderEffect = () => {
     setCurrentUser(queryData.currentUser);
 
     if (isDefined(queryData.currentUser.currentWorkspace)) {
-      setCurrentWorkspace(queryData.currentUser.currentWorkspace);
+      setCurrentWorkspace({
+        ...queryData.currentUser.currentWorkspace,
+        defaultRole: queryData.currentUser.currentWorkspace.defaultRole ?? null,
+      });
     }
 
     if (isDefined(queryData.currentUser.currentUserWorkspace)) {