MFC r279249, r279250, r279257:

MFC r279249, r279250, r279257:

 r279249:
  Add 'cloudware-install' target to handle copying cloud
  disk images to a directory within DESTDIR.

  Add CLOUDINSTALL variable to automatically generate the
  actual list of install targets.  While here, rename the
  cloud-specific names from 'vm-' to 'cw-' to avoid naming
  collisions.

  Add AZURE_DISK, GCE_DISK, and OPENSTACK_DISK output file
  variables.

  Add 'cloudware-install' to the 'install' target.

 r279250:
  Remove a stale comment.

 r279257:
  Add a CLOUDPACKAGE variable to contain a list of targets for
  post-install packaging cloud provider images.

  Add a 'gce-package.sh' script to generate the final output
  image ready for upload to the GCE platform.  Right now, this
  is the only image that has a specific output format (GNU-tar),
  and this implementation is expected to be temporary.

  This is not directly connected to the other release targets.

Sponsored by:	The FreeBSD Foundation

git-svn-id: svn://svn.freebsd.org/base/stable/10@279558 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f