Allow using ID range 3000-4999

[Dinoguy1000]

Per Extension default namespaces on MediaWiki.org, the ID range of 3000-4999 is reserved for sites to define their own custom namespaces; several other namespace management extensions already use this range for that purpose. There's also guidance that IDs above 10,000 are reserved for future use and should not be used by extensions or sites for their custom namespaces, so this should probably be made the default for new installations of this extension.

[wgevaert]

This would only allow this extension to create 500 namespaces, that may not be suitable for all use cases. Nevertheless, having this as a possibility might be a good idea.

[Dinoguy1000]

It would allow 1000 namespaces+talkspaces, not 500.