`CREATE DATABASE` location

#451 implemented support for `CREATE DATABASE` queries.
It includes two tests for the query.

`Statement::CreateDatabase` has two additional fields: `location` and `managed_location`. The syntax for these is not detailed; neither in the PR, nor anywhere else I can find.

1. Perhaps this could be detailed in the docs
2. Perhaps tests could be added for these fields
3. What is the syntax for these fields?

Beginne mit der Durchsicht von PR #451 und den beiden bestehenden CREATE DATABASE-Tests. Untersuche anschließend Statement::CreateDatabase, einschließlich der Felder location und managed_location. Ermittle die Syntax für beide Felder und dokumentiere sie, indem du Tests hinzufügst, die die Syntax abdecken, damit das Verhalten eindeutig ist.

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