Handle the new data- attributes for text formats with filter_html

Linkit 5.x is altering the default link plugin (drupallink) instead of define its own.

We therefor have to figure out a way to set the data- attributes on the <a> tag when enabling Linkit on the default link plugin in case the text format uses the filter_html filter.

• data-entity-type
• data-entity-uuid

Or we can just show a text in the link plugin settings page, next to where you choose which Linkit profile to use for the link plugin, that tells the user to manually add the two data- attributes to the <a> tag.