feature(models): add Status to Tenant model

[igorsimb]

Fixes #67, #58

Summary by CodeRabbit

• New Features
  • Added a "status" field with predefined choices (Trialing, Active, Exempt, Canceled, Trial expired) to the "Tenant" model for better status management.
  • Introduced TenantFactory and UserFactory for streamlined creation of Tenant and CustomUser instances in tests.
• Bug Fixes
  • Modified the CustomUser model to include a related_name attribute for the tenant field, ensuring clearer relationships and queries.
• Refactor
  • Improved database performance by adding indexes to the CustomUser and Tenant models.
  • Simplified test setups by removing redundant pytest decorators and adjusting test markers.
  • Enhanced test coverage for accounts and main app models, including user existence, tenant functionalities, and item model creation.
• Chores
  • Adjusted test configurations and introduced a fixture to ensure consistent test environment setup.

[coderabbitai[bot]]

Walkthrough

The recent updates focus on enhancing the Tenant and CustomUser models within a Django application. Key modifications include the introduction of a status field in the Tenant model with predefined choices and indexing for improved query performance. The CustomUser model now references the Tenant model, with added indexing for the tenant field to optimize database operations. Additionally, the creation of a Tenant instance is automated for new CustomUser entries without a specified tenant. Comprehensive testing ensures these changes align with the objectives for database efficiency and model functionality.

Changes

Files	Change Summary
accounts/migrations/..., main/migrations/...	Introduced migrations for altering CustomUser and Tenant models, including new fields and indexes.
accounts/models.py, main/models.py	Modified CustomUser and Tenant models to include new fields, indexes, and model options.
tests/accounts/..., tests/main/...	Updated and added tests for CustomUser and Tenant functionalities, including new fields and model interactions. Adjusted testing setup by removing pytest decorators and introducing a new fixture.
tests/factories.py	Introduced TenantFactory and UserFactory for creating model instances in tests.