Create output directory if it doesn't exist

[gdamjan]

Currently componentize-py fails if the out directory doesn't exist

$ componentize-py -w spin-http componentize spin_py_demo -o nonexistant/main.wasm
Traceback (most recent call last):
  File "/home/damjan/projects/spin-py/.venv/bin/componentize-py", line 10, in <module>
    sys.exit(script())
             ~~~~~~^^
AssertionError: No such file or directory (os error 2)

in this case it should really try to create the output directory.