[FEATURE REQUEST] Support for creating nested namespaces recursively

### Is your feature request related to a problem? Please describe.

Currently , Polaris doesn't support creating namespaces which do not exists recursively . for spark.sql('create namespace n1.n2.n3') to work , n1 and n2 should already be there in place , or else the SQL would fail.

To bring in compatibility with other catalog's SQL, would it make sense to support creating nested namespaces recursively? Or is there any reason behind not doing this?

### Describe the solution you'd like

allow users to create nested namespaces with a single SQL command,

### Describe alternatives you've considered

The only alternative we have is constructing multiple SQL queries which is difficult compared to what other catalog offers.

### Additional context

_No response_

The issue names no source files or tests. Start by tracing how the catalog handles CREATE NAMESPACE for dotted names, then identify the existing namespace-creation tests. Done means one SQL command creates n1, n2, and n3 when the parent namespaces are absent, while preserving current behavior for existing namespaces.

Written by the indexing model from the issue text.