[TECH DEBT]: Split `CatalogSchema` into `Catalogs` and `Schemas`

[JCZuurmond]

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Problem statement

Split CatalogSchema into Catalogs and Schemas and move Catalogs out of hive_metastore/ module.

This PR struggles with CatalogSchema being together as it only want to create a catalog but CatalogSchema requires workspace related objects (like the SQLBackend) that is not present on the account level.

Proposed Solution

Split CatalogSchema into Catalogs and Schemas and move Catalogs out of hive_metastore/ module.

Additional Context

Note that catalog_schema.py is inconsistent naming with the other modules which use plural instead of singular form