deployed artifacts naming improvements

This is just the preparation for last bigger change to have consistent naming across all deployed artifacts. These 6 preparation commits shouldn't change any names yet, verified with core-image-base for qemux86 and raspberrypi3.

Using more variables allows to simplify appending some release information to the images, corresponding kernels and other artifacts as shown in:
https://github.com/webOS-ports/meta-webos-ports/commit/6fd0af4dbd3da396d41e330f9dd932e859c5f7f0

The recipes and classes which generate or use new artifacts might need to inherit kernel-artifact-names and update the variables as shown in example here:
https://github.com/shr-distribution/meta-smartphone/commit/5e70b3779e0d6c90fbfbafeca2c9e4c4943d1196

The final change which allows to re-use do_deploy from sstate, while still producing the consistent naming scheme (e.g. image as well as kernel will have the same DATETIME stamp or for release the same build number even when the kernel.do_deploy was used for multiple builds will look like this:
http://git.openembedded.org/openembedded-core-contrib/commit/?h=jansa/master&id=91e5b30f10f24210c31d3f5ec137de22f89967d7

The following changes since commit 176e50fb177dc40e439700d5f3f838dd7eaaa427:

runtime selftest: limit kernel hw bp arches (2018-08-16 22:40:06 +0100)

are available in the Git repository at:

git://git.openembedded.org/openembedded-core-contrib jansa/kernel
http://cgit.openembedded.org/openembedded-core-contrib/log/?h=jansa/kernel

Martin Jansa (6):
bitbake.conf, kernel-artifact-names.bbclass: introduce
IMAGE_VERSION_SUFFIX instead of using DATETIME directly
kernel-artifact-names, kernel-fitimage: add KERNEL_FIT_BASE_NAME,
KERNEL_FIT_SYMLINK_NAME variables
kernel*.bbclass: rename *_SYMLINK_NAME variables to *_LINK_NAME and
*_BASE_NAME to *_NAME
kernel-artifact-names.bbclass, kernel.bbclass: remove prefix and
extension from MODULE_TARBALL_* variables
kernel-artifact-names.bbclass: Add 2 more variables to make it easier
to change all names with one variable
kernel.bbclass: rename type variable to imageType

 meta/classes/kernel-artifact-names.bbclass | 27 +++++-----
 meta/classes/kernel-devicetree.bbclass     | 22 ++++----
 meta/classes/kernel-fitimage.bbclass       | 34 +++++-------
 meta/classes/kernel.bbclass                | 62 +++++++++++-----------
 meta/conf/bitbake.conf                     |  5 +-
 5 files changed, 70 insertions(+), 80 deletions(-)

2.17.1