Namespaces can be created outside the parent catalog's allowedLocations

[eric-maynard]

Describe the bug

The default table location overlap check relies on the idea that the logical hierarchy of tables & namespaces within a catalog is aligned with the physical arrangement of those tables & namespaces within one of the catalog's allowed locations. However, it's currently possible to create a namespace outside of the parent catalog, which breaks not only this assumption but also the fundamental constraint of a catalog having a list of allowed locations at which its tables may be found.

To Reproduce

Create a catalog, such as with:

./polaris \
    catalogs \
    create quickstart_catalog \
    --storage-type file \
    --default-base-location 'file:///tmp/quickstart'

Create a namespace:

./polaris \
    namespaces \
    create \
    --catalog quickstart_catalog \
    --location 'file:///tmp/ns' \
    ns