Improve the workitem handler consumability

Improve the workitem handler consumability

NAMING: Workitem Handler name is not clear for newbie, it would be more appropriate something like: "reusable service"

There are 3 persona involved:

• the process author: an expert of process modelling which main goal is to reuse existing services with a black box approach
• the integration developer: an expert java developer that has to provide a reusable services to the process author. He know how to integrate backend system leveraging Java APIs.
• the process administrator: is in charge for managing the runtime environment.

Process Author:

1. He has to find quickly the service and import into the current project. The service registry should be reachable at higher level, maybe in the project configuration panel, then the WorkItem Handler should be available among the project assets.
2. The WorkItem Handler is defined by its interface (input / output), the import action can have as side effect the inclusion of a domain specific model (a maven dependency). E.g. If I import the "telegram WIH", I import new Data Object: "TelegramMessage" that will be used as type for the input parameter.
3. The Business Central should host a service registry but it can even federate external ones. It's quite important that an organization can easily share the common reusable WIH in one place in the BC.

Integration Developer:

1. S/He needs a registry publishing procedure for her/his WIH: it can be interactive but even driven by command line (maven plugin?)
2. S/He has to develop the WIH with less possible constrains using thirty party libraries avoiding libraries clash (the WIH should run in an isolated classloader).

Process Administrator

1. S/He has to deploy the BPM project without worrying of the WIH used. The deployment artifact should bring even the dependent WIH. When the process administrator deploy a new project the deployment procedure should automatically set up the dependent WIHs. Another option could be that the deployment procedure stops and warns about the lack of the required WIH.