[FEATURE] Pipes for Visual Data Service design

[josvanroosmalen]

The idea here is to have a low code option for Data Service. Here we have an "DataServiceInput" block, and a "DataServiceOutput" block.

Aim to get this in release 3.0 after the native Javascript generator.

[grtjn]

Alternative approach, as suggested offline: allow calling generated pipes code 'manually' for self-written code. That way it can be invoked in any context, even rest extensions, or random other sjs (or xqy?) code..

Could also be complementary. Generate code into libraries, and provide ready to use endpoint code and such that make use of the libs.