feat: expose Talos node labels as a machine configuration field

[sauterp]

We add the nodeLabels key to the machine config to allow users to add node labels to the kubernetes Node object. The NodeLabels controller reads the nodeLabels from the machine config and applies them via the kubernetes API. talosctl will throw an unknown keys error if edit mc is called on a node with this change.

Fixes #6301

Signed-off-by: Philipp Sauter [email protected]