feat(core): Allow user role modification (#7797)

https://linear.app/n8n/issue/PAY-985

```
PATCH /users/:id/role
  unauthenticated user
    ✓ should receive 401 (349 ms)
  member
    ✓ should fail to demote owner to member (349 ms)
    ✓ should fail to demote owner to admin (359 ms)
    ✓ should fail to demote admin to member (381 ms)
    ✓ should fail to promote other member to owner (353 ms)
    ✓ should fail to promote other member to admin (377 ms)
    ✓ should fail to promote self to admin (354 ms)
    ✓ should fail to promote self to owner (371 ms)
  admin
    ✓ should receive 400 on invalid payload (351 ms)
    ✓ should receive 404 on unknown target user (351 ms)
    ✓ should fail to demote owner to admin (349 ms)
    ✓ should fail to demote owner to member (347 ms)
    ✓ should fail to promote member to owner (384 ms)
    ✓ should fail to promote admin to owner (350 ms)
    ✓ should be able to demote admin to member (354 ms)
    ✓ should be able to demote self to member (350 ms)
    ✓ should be able to promote member to admin (349 ms)
  owner
    ✓ should be able to promote member to admin (349 ms)
    ✓ should be able to demote admin to member (349 ms)
    ✓ should fail to demote self to admin (348 ms)
    ✓ should fail to demote self to member (354 ms)
```

packages/cli/src/databases/entities/Role.ts

@@ -7,7 +7,7 @@ import type { SharedCredentials } from './SharedCredentials';
 import { WithTimestamps } from './AbstractEntity';
 import { idStringifier } from '../utils/transformers';
 
-export type RoleNames = 'owner' | 'member' | 'user' | 'editor';
+export type RoleNames = 'owner' | 'member' | 'user' | 'editor' | 'admin';
 export type RoleScopes = 'global' | 'workflow' | 'credential';
 
 @Entity()