padding bottom hack on youtube iframe and no width
new size field added to choose between fullWidth or custom for player size

is necessary for new responsive padding bottom style
add support for getComponentsByClass for StaticSelect generators

support is limited by not supporting looking up the first class
update old youtube videoWidths to new size mode
load cards assets only for backend
renamed videoWidth correctly for db design
Merge pull request #217 from kaufmo/3.7-responsive-youtube

responsive youtube iframe