#011442: Make the intention of the DatabaseSchema component clearer in the documentation

In the documentation of the DatabaseSchema component, it is not mentioned that the idea is to extract a database schema, from an existing source, like a database. Which might lead people to believe that you can use it, to create schemas from scratch by hand.

The latter is not trivial, as the xml format for the schemas is not documented.

Operating System:
PHP Version: (please be specific, like '4.4.3' or '5.1.5')
Database and version:
Browser (and version):