REST-API endpoint for User task form variables incl. properties and constraints

User Story (Required on creation)

As a WEB-UI developer i want to create custom forms for User tasks by calling the REST-API to get the defintion of the form.

Currently i need to parse the BPMN-XML to get the properties, constraints and defined fields.

With current API i can get only the fields for the user task. therefor i need to call "/variables" followed by "/form-variables" and remove all variables from the response of "/form-variables" returned by "/variables". Current REST-API does not provide properties and constraints

Functional Requirements (Required before implementation)

I need a REST-API endpoint similar to "/form-variables" returning the Form fields incl. properties and constraints, without variables from other scopes

Technical Requirements (Required before implementation)

Looking at the code i guess a new command needs to be implemented similar to GetTaskFormVariablesCmd called by a new REST endpoint

Limitations of Scope

Hints

Links

Breakdown

### Pull Requests