Add Qt for WebAssembly examples and demos

Initial batch of four:

	localfiles
	multicanvas
	mandelbtrot
	slate

See README.md for further description.
Status Job ID Name Coverage
  Build
failed #9401
build

 
  Test
skipped #9403
allowed to fail
code_quality
skipped #9402
test
 
Name Stage Failure
failed
build Build There has been a timeout failure or the job got stuck. Check your timeout limits or try again
No job trace