fix(content): responsive videos

- add JS to get all iframes with youtube or vimeo ,then add video-responsive css class
- update CSS to support responsive
8 jobs for fix/fit-videos in 3 minutes and 6 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  .Pre
passed #2546
install

00:01:27

 
  Test
passed #2552
lint

00:00:29

passed #2547
test

00:00:30

failed #2550
lint

00:00:10

failed #2551
lint

00:00:10

failed #2548
lint

00:00:15

 
  Build
passed #2553
build

00:00:38

failed #2549
build

00:00:09