feat: make role name unique and remove key usage

packages/backend/src/graphql/mutations/create-user.ee.js

@@ -32,7 +32,7 @@ const createUser = async (_parent, params, context) => {
     userPayload.roleId = params.input.role.id;
   } catch {
     // void
-    const role = await Role.query().findOne({ key: 'admin' });
+    const role = await Role.findAdmin();
     userPayload.roleId = role.id;
   }
 

packages/backend/src/graphql/mutations/register-user.ee.js

@@ -15,7 +15,7 @@ const registerUser = async (_parent, params) => {
     throw new Error('User already exists!');
   }
 
-  const role = await Role.query().findOne({ key: 'user' });
+  const role = await Role.query().findOne({ name: 'User' });
 
   const user = await User.query().insert({
     fullName,