As modelling User, I can model form fields on the properties panel

AT:

• new tab for user tasks named "Form Fields"
• supported form fields can be edited --> discussion needed, see linked issues
• include version hint: "This feature is supported for version 7.1 and higher"

<userTask id="usertask" name="Task" camunda:candidateGroups="dummy">
<extensionElements>
<camunda:formData>
<camunda:formField
id="stringField" label="String Field" type="string"
defaultValue="someString">
<camunda:properties>
<camunda:property id="icon" value="user-name"/>
</camunda:properties>
<camunda:validation>
<camunda:constraint name="max-length" config="10" />
<camunda:constraint name="min-length" config="5" />
</camunda:validation>
</camunda:formField>
<camunda:formField
id="longField" label="Long Field" type="long"
defaultValue="1" />
<camunda:formField
id="booleanField" label="Boolean Field" type="boolean"
defaultValue="true" />
<camunda:formField
id="dateField" label="Date Field" type="date"
defaultValue="10-JAN-2013">
<camunda:properties>
<camunda:property id="datePattern" value="dd-MMM-yyyy" />
</camunda:properties>
</camunda:formField>
<camunda:formField
id="enumField" label="Enum Field" type="enum"
defaultValue="a">
<camunda:value id="a" name="A"/>
<camunda:value id="b" name="B"/>
<camunda:value id="c" name="C"/>
</camunda:formField>
</camunda:formData>
</extensionElements>
</userTask>