Moved all YouTube related URLs to a separate namespace.

cms/djangoapps/contentstore/views/transcripts_ajax.py

cms/envs/acceptance.py

cms/envs/common.py

common/lib/xmodule/xmodule/js/fixtures/video.html

common/lib/xmodule/xmodule/js/fixtures/video_all.html

common/lib/xmodule/xmodule/js/fixtures/video_html5.html

...on/lib/xmodule/xmodule/js/fixtures/video_no_captions.html

...on/lib/xmodule/xmodule/js/fixtures/video_yt_multiple.html

common/lib/xmodule/xmodule/js/src/video/01_initialize.js

common/lib/xmodule/xmodule/video_module/transcripts_utils.py

common/lib/xmodule/xmodule/video_module/video_module.py

lms/djangoapps/courseware/tests/test_video_mongo.py

lms/envs/acceptance.py

lms/envs/common.py

lms/templates/video.html