XD-2061 Add Redis sink module

 - Add Redis sink with the following options:
    - topic (a SpEL expression)
    - hostname, port and password
For the record, those constructs in xml are exactly what we wanted to move away **from** when designing the module options support. For one thing, some computations were expected to be more complicated and read better in java rather than in SpEL (one could argue this turned out to only represent a small fraction of cases), but more importantly, those SpEL constructs fail to capture the logic for default values and expose them to users (e.g. in `module info`), etc.