Configurable package namespaces/prefixes (#247) Fixes: #246 Implemented according to the proposal I posted in #246. Tested manually with the CertManager CRDs, with and without the new CLI option, for `nodejs`, `python`, `dotnet` and `java`. As it needs to be, without the namespace/prefix option, I could verify the default value was still used. With the new namespace/prefix option, the value was integrated correctly in the generated files.