Add JSON schema definitions for various system components

- Introduced VulnerabilitySeverity schema to define severity levels of security vulnerabilities.
- Added DatabaseLevelIsolationStrategy schema for database-level isolation configurations.
- Created Feature schema to outline feature codes, labels, descriptions, and types.
- Implemented LevelIsolationStrategySchema for schema-level isolation strategy configurations.
- Defined License schema to manage license details including space ID, plan code, and status.
- Added LicenseMetricType schema to specify types of license metrics.
- Created Plan schema to outline plan details including code, label, features, and limits.
- Introduced RegistryConfig schema for registry configurations including upstream settings and access control.
- Added RegistrySyncPolicy schema to define synchronization strategies for registries.
- Created RegistryUpstream schema for upstream registry configurations.
- Implemented RowLevelIsolationStrategy schema for row-level isolation strategy settings.
- Defined Tenant schema to manage tenant details including ID, name, and quotas.
- Added TenantIsolationConfig schema to configure isolation strategies for tenants.
- Created TenantIsolationLevel schema to specify isolation levels for tenants.
- Introduced TenantQuota schema to manage tenant quotas for users, storage, and API rate limits.
- Added TenantSecurityPolicy schema to define security policies for tenants including encryption and access control.

Author: hotlong