[Request] Document the outputType parameter in module READMEs

## WHAT

Several modules expose an `outputType` parameter, but it isn’t documented in their READMEs.

## WHY

For example, the JDBC sink module doesn’t support the `ELEMENT` type, which makes it incompatible with the Filter transformer’s default output. As a workaround, users currently have to set the (undocumented) `outputType ` parameter manually.