Beam I/O JDBC support

[diethardsteiner]

As a developer I'd like to use a Kettle Beam I/O JDBC input and output step that makes use of the respective Beam API feature (see here).

[mattcasters]

Better to support all input and output steps.
These other IO APIs are doing the same but with fewer features compared to the Kettle steps.

[mattcasters]

You can now simply use a Table Output step in Kettle.
Setting the step copies to BEAM_OUTPUT reduces the number of threads to 1 by doing a grouping/flattening before the step.