Create "array" field type

[Barrett Alexander]

Allow configuring a repeatable collection of values. This should be stored as an array of key-value paired objects. For example, this is how it would be saved as JSON.

{
    items: [
        {name: 'Red', value: '#ff0000'},
        {name: 'Blue', value: '#0000ff'},
        {name: 'Green', value: '#00ff00'}
    ]
}

[Barrett Alexander]

This has been implemented as field "Collections"