Implement User endpoints

[Matthew-Wise]

GET Endpoints

• [ ] GET /umbraco/management/api/v1/item/user
• [ ] GET /umbraco/management/api/v1/user
• [ ] GET /umbraco/management/api/v1/user/{id}
• [ ] GET /umbraco/management/api/v1/user/{id}/2fa
• [ ] GET /umbraco/management/api/v1/user/{id}/calculate-start-nodes
• [ ] GET /umbraco/management/api/v1/user/{id}/client-credentials
• [ ] GET /umbraco/management/api/v1/user/configuration

POST Endpoints

• [ ] POST /umbraco/management/api/v1/user
• [ ] POST /umbraco/management/api/v1/user/{id}/change-password
• [ ] POST /umbraco/management/api/v1/user/{id}/client-credentials
• [ ] POST /umbraco/management/api/v1/user/{id}/reset-password
• [ ] POST /umbraco/management/api/v1/user/avatar/{id}

PUT Endpoints

• [ ] PUT /umbraco/management/api/v1/user/{id}

DELETE Endpoints

• [ ] DELETE /umbraco/management/api/v1/user
• [ ] DELETE /umbraco/management/api/v1/user/{id}
• [ ] DELETE /umbraco/management/api/v1/user/{id}/2fa/{providerName}
• [ ] DELETE /umbraco/management/api/v1/user/{id}/client-credentials/{clientId}
• [ ] DELETE /umbraco/management/api/v1/user/avatar/{id}