feature videos on DVC sites

[elleobrien]

From a chat with @shcheklein:

We can add links to our YouTube channel in a few places on the DVC site, and also maybe on cml.dev and iterative.ai.

• Add link to YouTube channel close to the video on our landing page
• Add a footer: "Subscribe to our channel to learn about MLOps!"
• Maybe something on our Community page? Could replace one of the sections that is underused (maybe Events, since this is a bit unused during COVID times?)
• Make room for Getting Started videos in each of the four Getting Started docs.

Where we may need some design support:

• Placing a link/banner in the right place on our landing page
• Finding good spots on the cml.dev and iterative.ai site to encourage checking out the videos
• On docs pages that will have a video embedded, where does it make sense to add it? Should it be on the top or bottom of the page?

[julieg18]

We have links to youtube on all our site's footers and/or headers, have an issue (#2603) opened for adding youtube to our community page, and have added youtube videos to our docs!