orgnize the views and serilizers on the dashboard folder

[mkurkar]

Related Issue:

This pull request introduces a comprehensive set of serializers for the dashboard API, organizing them by theme (common, learners, courses, roles, config, and statistics). It establishes a unified structure for serialization, permission handling, and read-only endpoints, which will help standardize API responses and improve maintainability.

Core API Structure

• Created an __init__.py in the serializers package to aggregate and expose all serializers, grouped by their respective themes (common, learners, courses, roles, config, statistics), and defined the __all__ list for explicit exports.

Common Serializers & Mixins

• Added DataExportTaskSerializer, ReadOnlySerializer, and FxPermissionInfoSerializerMixin in common.py to provide reusable serialization logic, permission information fields, and HTML sanitization for notes.

Config Serializers

• Implemented serializers for configuration-related objects, including file upload validation, tenant asset management, and tenant configuration details, with custom permission checks and validation logic.

Role Serializers

• Developed UserRolesSerializer to serialize user role information, including global and tenant-specific roles, and added logic for filtering and constructing role data based on permissions and query parameters.

Statistics Serializers

• Added serializers for statistics endpoints, supporting read-only access and structured representation of aggregated counts and query settings.