Move the CLI to a framework like Cobra #936
Description
The following issue is about moving the CLI to a proper framework like cobra which would give us a few things for granted
Benefits:
- Automatic help generation and version handling
- Built-in shell completion support (bash/zsh/fish/PowerShell)
- Better flag validation and error messages
- Easier to add new commands/subcommands
- Consistent with popular CLI tools (kubectl, gh, hugo, etc.)
- More testable command structure