Remove/rename old well-known hostnames to NICo branding

[ajf]

Previous versions of NICo were known by other names, namely carbide and forge. The DNS names used were generated based on that (e.g. carbide-pxe.forge).

For v2.0.0 we should change these to NICo variants for things that are internally managed.

• grpc.nico (gRPC API)
• pxe.nico (PXE SErvice (template generator))
• pxe-static.nico (Optional artifact cache to reduce load on Axum service serving static files.)

Not every service needs one of these well known hostnames. Alternatively, we just make these configurable per-site so we don't have a dependency on overriding DNS names.

[Matthias247]

Configurable is unfortunately not that easy. A lot of services which are meant to pull configs are using the addresses. DPU-agent and scout are among them. If the address would be configurable, they would need to receive that config via some other means.

For the list: there is again also ntp.nico