[Integrations] All commands should have a --flat flag for integrations output

[lcfd]

At the moment the output of most commands isn't digestible for terminal tools.

For example, the upcoming trak.nvim plugin or even pipe commands like | grep can benefit from this change.

A similar feature is already there for the Starship integration (-s or --starship).
The intention is to move everything to the more generic flag --flat.