Add responsive embed support to ProPhoto for WordPress 5

[postmastersteve]

This Github issue is synchronized with Zendesk:

Ticket ID: #193338 Priority: normal Group: Developers Requester: steve@pro.photo Organization: Downshift Issue escalated by: Josh Arens

Original ticket description:

Adds support for responsive embeds (e.g. YouTube embed blocks, etc.):

add_theme_support( 'responsive-embeds' );

I'd like this for our help site at the least.

Steve Post
ProPhoto Support

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[lalunecreative]

We need this video in P7 pretty bad too.

[postmastersteve]

duplicate of #734