Allow editor to build dynamic form field dependencies

Description

Episerver Forms now lets you hide or show a field based on input to another form field. You create rules for field elements on a new Dependencies tab in the element properties.
You can create dependency rules for the following field element types:

• Choice element
• ImageChoice element
• Number element
• Range element
• Selection element
• TextArea element
• TextBox element
• Url element
• FileUpload element
• Multi or single choice element

Note: Custom elements (like the ones in Forms.Sample) may not work well with field dependency by default. If you create custom elements, you are responsible for making them compatible with field dependency.