image_types_wic.bbclass: Copy the .wks and .env files to deploy image dir

image_types_wic.bbclass: Copy the .wks and .env files to deploy image dir

When using a .wks.in file, the only place that the generated .wks file
exists in the tmp/work area.  A copy should be left behind in the
deploy directory so that you can easily run the wic tool to
re-generate or modify a new image without running bitbake.  Custom
.wks.in files can reference any number of bitbake variables, so it is
important to save the result.

below is an example of using the generated .wks file in the deploy
area.  The full name of my generated .wks file was
core-image-minimal-ostree-uboot-ab.wks, but since you usually only
have a single .wks file per image you can use a wild card like:

  cd tmp*/deploy/images/*
  wic create --vars . -e core-image-minimal -s -m core-image-minimal-*.wks

(From OE-Core rev: 42293d75404486e20db9f7a80d0d1756887b576d)

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>