Update root API view and add seed management documentation

[6reenhorn]

This pull request introduces new features and improvements to both the mock data seeding command and the landing page, as well as adds comprehensive documentation for seed data management. The main changes are the addition of new command-line options for better control over mock data, enhancements to the landing page's responsiveness and layout, and the creation of a dedicated documentation file for seed management.

Mock Data Seeding Improvements:

• Added --flush option to the seed_mock_data management command to delete all institutions and queue entries before seeding, enabling a clean slate for testing.
• Introduced --close-count option to randomly set a specified number of institutions to CLOSED status for simulation purposes. [1] [2]

Landing Page UI Enhancements:

• Improved landing page CSS for better responsiveness, including flexible layouts, padding adjustments, and media queries for small screens. [1] [2] [3]

Documentation:

• Added seed-management.md with detailed instructions and examples for using the mock data seeding command and its new options.

[Gshadow2005]

IMPSV