Renamed `applyPromptFlags` to `applyGenerationFlags` and added `validateGenerationFlags`
`lmcli chat` now supports common prompt flags (model, length, system prompt, etc)
- Split pkg/cli/cmd.go into new pkg/cmd package - Split pkg/cli/functions.go into pkg/lmcli/tools package - Refactor pkg/cli/openai.go to pkg/lmcli/provider/openai Other changes: - Made models configurable - Slight config reorganization