New built-in ACF + page template targeting.

[ccorda]

We currently have a wpgraphql workaround: Add ACF to Page Templates -- looks like it'll shortly be fixed, and we can remove ours

wp-graphql/wp-graphql-acf#229 (comment)

[ccorda]

Also we don't need to rely on generateFlex(type) any more, since we can now do:

flexContent {
        ... on Template_Flex_Acfflex_FlexContent_WysiwygContent {
          ${fragmentSectionOptions}
          fieldGroupName
          contentWidth
          sectionHeading
          wysiwygContent
        }

[ccorda]

This is in now.