Add support for GenAI instrumentation

[xuan-cao-swi]

We probably should start to support some of the GenAI instrumentation unless they have native instrumentation.

gem 'openai'                           # Official OpenAI API client
gem 'ruby-openai'                      # OpenAI API client
gem 'langchainrb'                      # LangChain for Ruby
gem 'google-cloud-ai_platform'         # Google Vertex AI
gem 'gemini-ai'                        # Google Gemini AI (maybe should focus on the official google-cloud-ai_platform)

Spec: https://opentelemetry.io/docs/specs/semconv/gen-ai/