GNOME Data Access 5 manual: Various API changes

## Various API changes

- `GdaFieldAttributes` has been renamed `GdaColumn`

- The `GdaParameter` is now an object, and it is extensively used within `GdaParameterList` objects. Each `GdaParameterList` object represent a vector of parameters (which may or may not have values assigned) and is the base of the `GdaDataModelIter` iterator object. The `GdaParameter` API has been altered.

- The `GdaExport` class has been removed, the features it offered are now implemented in each `GdaDataModel` object.

- `GdaSelect` has been renamed `GdaDataModelFilterSQL`

- The `GdaTable` class has been replaced by the `GdaDataModelQuery` class: it's a data model which can refresh itself and can be configured to be updatable, it's not limited to a database table.

- The `GdaXmlDatabase` has been removed and the default database is now SQLite which is a complete RDBMS in a file

- All the `gda_xql_*()` functions have been removed because they were unused and unmaintained.

- The 'xml' provider has been removed as it did not work correctly and has been replaced by the SQLite provider as the provider to have serverless databases.