BPMN editor to support "expression" in Data IO on process side

The goal is to add expressions support in any of both Data Inputs and Data Outputs declarations.

An expression is given by the following syntax:

#{expression}

This way, the actions to perform are:

• On the UI side
  • For Data Inputs -> Add another dropdown option, in addition to the existing constant one, for expression
  • For Data Outputs -> Add a dropdown option for expression (constant is not allowed for Data Outputs)

• On the marshalling side
  • Once having an expression value, it must NOT be encoded in the resulting XML file, allowing the engine the properly parsing for the expression and further runtime evaluation
  • PS: Nothing has to change in case for constant - value will be encoded as actually it does

Notes:
Engine: https://github.com/kiegroup/kogito-runtimes/pull/314
Example in Eclipse :