Assign the same property multiple times in a view helper

[brotkrueml]

As an integrator I want to assign the same property multiple times as a string in a view helper. For example: the "sameAs" property in an "Organization" type to set additional profiles.

Example output:

<script type="application/ld+json">
{
    "@context":"http://schema.org",
    "@type":"Organization",
    "name": "Acme Ltd.",
    "sameAs": [
        "http://example.org/profile1",
        "http://example.org/profile2",
        "http://example.org/profile3"
    ]
}</script>

The multiple assignment of a type is already implemented with the usage of child type view helpers.

Acceptance criteria:

• It is possible to add a property value multiple times as a string in a view helper.
• The documentation is adjusted.