classes/buildhistory: implement history collection for SDKs

SDKs are constructed in a similar manner to images, and the contents can
be influenced by a number of different factors, thus tracking the
contents of produced SDKs when buildhistory is enabled can help detect
the same kinds of issues as with images.

This required adding POPULATE_SDK_POST_HOST_COMMAND and
SDK_POSTPROCESS_COMMAND variables so that data collection functions can
be injected at the appropriate points in the SDK construction process,
as well as moving the list_installed_packages and
rootfs_list_installed_depends functions from the rootfs_{rpm,ipk,deb} to
the package_{rpm,ipk,deb} classes so they can also be called during
do_populate_sdk as well as do_rootfs.

Implements [YOCTO #3964].

(From OE-Core rev: c3736064483d4840e38cb1b8c13d2dd3a26b36aa)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/populate_sdk_base.bbclass

@@ -86,6 +86,8 @@ fakeroot populate_sdk_image() {
 
 	# Link the ld.so.cache file into the hosts filesystem
 	ln -s /etc/ld.so.cache ${SDK_OUTPUT}/${SDKPATHNATIVE}/etc/ld.so.cache
+
+	${SDK_POSTPROCESS_COMMAND}
 }
 
 fakeroot create_sdk_files() {