Implement selection of dataTypesToSign for signing tasks in process config panel

[standeren]

Description

Signing tasks must have defined xml elements in bpmn process file of which data types to sign, meaning what data types that should be added the signature field after the actual signing when the app is running.
There should be a multiselect dropdown in the config panel (only for taskTypes signing) where the user can select from all data types in appmetadata. There should also be some information of what the user selects here since it is not the same as selecting data models for a data task.
When the data types are selected in the multiselect they should be added to the bpmn signing element on the dataTypes property, defined here (in SupportedPaletteProvider.js):

const extensionElements = bpmnFactory.create('bpmn:ExtensionElements', {
          values: [
            bpmnFactory.create('altinn:TaskExtension', {
              taskType: taskType,
              actions: bpmnFactory.create('altinn:Actions', {
                action: [
                  bpmnFactory.create('altinn:Action', {
                    action: 'sign',
                  }),
                  bpmnFactory.create('altinn:Action', {
                    action: 'reject',
                  }),
                ],
              }),
              signatureConfig: bpmnFactory.create('altinn:SignatureConfig', {
                dataTypesToSign: bpmnFactory.create('altinn:DataTypesToSign', {
                  dataTypes: [], // This property should be updated with bpmnFactory.create('altinn:DataType', { dataType: [DATA_TYPE_ID]}),
                }),
                signatureDataType: `signatureInformation-${generateRandomId(4)}`,
              }),
            }),
          ],

To update the property use modeling.updateModdleProperties(...)

See EditActions for inspiration.