docs: Add Comprehensive Access Management Documentation

[vairav]

Summary

• Adds complete documentation for the CWMS Access Management system
• Provides 30+ markdown files covering all aspects of the entire Access Management platform
• Integrates with existing Sphinx documentation structure

Key Topics Covered

• Authorization flow with sequence diagrams
• Component architecture with Mermaid diagrams
• All 8 user personas (Admin, Database Admin, Data Entry, etc.)
• Office-based filtering and embargo rules
• Java helper class usage
• Environment variable reference
• CLI and Web UI usage guides

Changes

• Updated docs/source/conf.py for new section
• Updated docs/source/index.rst to include access-management

Test Plan

• Run make html in docs directory to verify Sphinx builds
• Verify all internal links resolve correctly
• Check Mermaid diagrams render properly
• Review code examples for accuracy