Add comprehensive vLLM and Ollama distribution documentation

- Created detailed vLLM distribution guide with GPU/CPU variants, configuration examples, and best practices
- Created comprehensive Ollama distribution guide with model management, API usage, and troubleshooting
- Added new 'Distributions' section to navigation with dedicated pages for each distribution type
- Includes production and development examples, resource planning, and scaling strategies
- Clearly distinguishes supported distributions from BYO (bring-your-own) custom image approaches

Signed-off-by: Adel Zaalouk <azaalouk@redhat.com>

Author: zanetworker