feat(groups): implement group creation functionality and refactor related components

- Removed organization dependency from group creation logic.
- Introduced new route and use-case for creating groups.
- Refactored form handling for group creation into a reusable GroupForm component.
- Updated API calls to support new group creation endpoint.
- Adjusted tests to reflect changes in group creation logic and validation.
- Removed obsolete organizations route and related components.
- Updated breadcrumb navigation and routing for group management.

apps/backend/src/http/problem-builders.ts

@@ -47,23 +47,6 @@ export function forbiddenProblem(params: {
   };
 }
 
-export function organizationNotFoundProblem(id: string): ProblemDetails {
-  return {
-    type: `${PROBLEM_DOMAIN}/problems/organization-not-found`,
-    title: 'Not Found',
-    status: 404,
-    detail: `Organization ${id} was not found.`,
-    code: 'organization_not_found',
-  };
-}
-
-export function groupOwnerRequiredProblem(): ProblemDetails {
-  return forbiddenProblem({
-    detail: 'Only the organization owner can create the group.',
-    code: 'group_owner_required',
-  });
-}
-
 export function databaseUnavailableProblem(params?: {
   instance?: string;
 }): ProblemDetails {