Add flag to command to generate routes without the server

[carnage]

We generate hosted and hostless routes based solely on the data in the openapi file, quite often this comes with servers that are either wrong or only applicable for a production environment.

It would be useful to be able to override this at route generation time, using a flag on the command.

After this is implemented, there will be three possible behaviours:

1. Generate using only servers/paths from the openapi spec file (current behaviour)
2. Ignore servers entirely and only generate the hostless version
3. Generate using the servers in the openapi spec file but also add a fallback hostless option to the router