Add support for preparing queries without parsing the placeholders

> Qt parses the sql for bind parameters for sqlite even though sqlite
> allows binding by name or position. (This may have been fixed in the
> regexp stuff, I wasn't involved in that conversation)

Because we support both named and positional binding we need to parse the query to make sure the binding works later.

We can add a directPrepare/nativePrepare function in QSqlResult that lets the user prepare a query without doing any placeholder checking, but there will most likely be some constraints on how the Qt bind-functions can be used for these queries.