Extend Video component for source prop

[zlonko]

Refactor filePath to source to allow for wider implementation (e.g., blogposts).

Context from review

Example:

interface Video {
  source: {
    webm: string
    mp4: string
  }
  loop: boolean
  caption: string
  title: string
}

Also, please identify opportunities to cut the blog SCSS out into Bootstrap utility classes. (Reference)

[zlonko]

It looks like component and interface were updated in https://github.com/sourcegraph/about/pull/5548. We can still use this issue to clean up the blog SCSS where possible!

[bretthayes]

The Video component updates were updated in #5493. Other styling initiatives will be tackled in #5381.