`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?

Start by reviewing PR #451 and the two existing CREATE DATABASE tests, then inspect Statement::CreateDatabase, including its location and managed_location fields. Establish the syntax for both fields and document it, adding tests that cover the syntax so the behavior is clear.

Written by the indexing model from the issue text.