Mark non-bootstrap commands as "in preview and under development"

[hiddeco]

With the bootstrap related commands of the CLI moving to stable, we need to guide our users to be aware that the other commands may still change over time. Given this, we should add a notice to these commands. For example something like:

Please note that this command (group) is in preview and under development. While we try our best to not introduce breaking changes, they may occur when we adapt to new features and/or find alternative ways to facilitate what it does.