support gzip in data: uri

[hrgdavor]

as discussed here https://github.com/jscad/OpenJSCAD.org/issues/1318#issuecomment-1896245210

it would be nice if jscad.app would unzip the script when mime type is application/gzip

I just took a script from jscad examples (gears)

content	size bytes	size bytes urlencoded
script raw	5.320	7.906
base64	7.096	7.104
gzip&base64	2.344	2.486

I was surprised to see urlencoding original script (7.9) is more overhead than base64 and then urlencode (7.1 k)

unless I miscalculated sth, gzip+b64 looks worth it