feat: add command that generates Git commands from natural language

Description

Add a command that generates Git commands from natural language. For example bin/glab git list commits create by Igor Drozdov will explain and suggest running git log --author='Igor Drozdov' command.

Related Issues

Related issue/epic: &10402

How has this been tested?

• Checkout on id-git-command-endpoint branch on Gitlab Rails: git checkout id-git-command-endpoint: gitlab!118120 (merged)
• Ensure Git Command feature is available to you:
  • Feature flags ai_git_command_ff, ai_experimentation_api, openai_experimentation are enabled
  • You are a member of Ultimate project
• Checkout on id-add-git-command branch (this Merge Request) in CLI
• Run make, now bin/glab binary is available for you
• Run bin/glab auth login, choose GitLab Self-hosted Instance and follow the steps to add your local env and local private token
• Run the git command: GITLAB_HOST=127.0.0.1:3000 bin/glab git ask list 10 commit titles:
  • git is the name of the command
  • All that goes after git is the natural language instructions that are sent to OpenAI

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation
• Chore (Related to CI or Packaging to platforms)
• Test gap