Move libopenjpeg to third_party/

We get to delete a whole bunch of fx_foo.c files that did nothing
but #include "foo.c" after defining _CRT_SECURE_NO_WARNINGS. Do this
from the .gyp/.gn files instead.

Also sort some "config"s in .gn file.

R=thestig@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/c7a17bf9cdb0d646aa8b653e6ab2678a1837ed6a

Review URL: https://codereview.chromium.org/1185373010.
80 files changed