refactor formbuilder

[sgratzl]

the form builder is the only piece left in the core using d3. I order to avoid using d3(v3) in the core the FormBuilder needs to be refactored.

At the same time it can be improved.

• Atm there is no overview what are the options for specific form element descs. A builder pattern could help in this case.
• similarly when calling getParameter the view has to now which are valid parameter and what will be the return value. When using an interface object (IParams...) everything could be typed.
• select vs select2 both have different styles how to provide data, name/value vs id/text in which forms (data, promise, ajax, ... This should be refactored
• simplify select2 similarly to the search box in the Dashboard application, i.e. implementing a custom transport method
• provide option to extend a form desc e.g. with a visualization to generate the parameter like a histogram selector

[sgratzl]

related #25

[thinkh]

It's also related to #52

[lehnerchristian]

we could either do this by using union types:

interface ISelectDesc {
  type: 'select';
  name: string;
}
interface ITextDesc {
  type: 'text';
  value: string;
}

declare type IDesc = ISelectDesc | ITextDesc;

const t: IDesc[] = [
  {
    type: "select",
    name: 'test'
  },
  {
    type: 'text',
    value: 'a'
  }
];

or with the builder pattern as a wrapper around the usual form description objects (i.e. the buildSelectElement function returns an object with the correct form element type):

buildSelectElement(ParameterFormIds.DATA_SOURCE).label('Data Source').required().useSession().optionsData(..).build()