Video link obfuscation. [BLD-1230]

cms/static/sass/elements/_xmodules.scss

common/lib/xmodule/xmodule/css/video/accessible_menu.scss

common/lib/xmodule/xmodule/css/video/display.scss

.../xmodule/xmodule/js/spec/video/video_context_menu_spec.js

common/lib/xmodule/xmodule/js/src/video/00_component.js

common/lib/xmodule/xmodule/js/src/video/00_i18n.js

common/lib/xmodule/xmodule/js/src/video/04_video_control.js

...ib/xmodule/xmodule/js/src/video/08_video_speed_control.js

...ib/xmodule/xmodule/js/src/video/095_video_context_menu.js

common/lib/xmodule/xmodule/js/src/video/10_commands.js

common/lib/xmodule/xmodule/js/src/video/10_main.js

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