Add type metadata to tags

@Damien, I saw that one. But if I'm right, that one is about translating the labels of the metatags, not the metatag values assigned to content.
In case of tag values, IMHO we should only translate those that are human-facing texts, not all of them.

This replaces the image annotation tag with a type tag. Used values are: integer, string, label, image, uri. I'm wondering how we could benefit from using TypedData here, as we may be able of take validation and other candies from that.

This patch doesn't contain any new tests, existings tests pass.

Oops, use the right typed data labels in the generator command.

@Damien, I tried to reuse types from Typed Data API, but not sure if it will make sense in every case. In any case we are not validating that the annotation contains a valid identifier in any case.

The difference between a string and a label is that the label is a translatable text, usually a text an end-user will see. The string usually is just a string which translation is a non-sense or problematic.
E.g. The Twitter Card type is a string (e.g. "summary" value), but the description metatag is a label. We want to translate our description values, but translating the twitter card type value can have unexpected results.

+++ b/src/Command/GenerateTagCommand.php
@@ -114,6 +114,15 @@ protected function interact(InputInterface $input, OutputInterface $output) {
+    // ToDo: Take this from typed data, so it can be extended?
+    $type_options = [
+      'integer',
+      'string',
+      'label',
+      'uri',
+      'image',
+    ];

As this ToDo I added says, we should be inferring these allowed values from TypedData API in case it is extended somehow. We just have a hard-coded list of allowed values now.

Thanks for committing, it makes sense to me to improve in further issues.