Add macro %isu_package to generate ISU Package

Add macro %isu_package to generate ISU Package

The macro makes it easier to prepare a separate configuration for ISU package.
Files from path %{BUILDROOT}/etc/isu/ are packed into a separate rpm
package: %{name}-isu

In addition, pattern occurrences are substituted:

  #NAME#             - %{name}
  #VERSION#          - %{version}
  #ISU_CONFIG_PATH#  - /etc/isu
  #ISU_INSTALL_PATH# - /opt/isu
  #ISU_RUN_PATH#     - /run/isu

Change-Id: Ia60a964165a9a838fb3422ded0410402924c5adf
(cherry picked from commit 0cb94f2a960168fb4cc6eed7acdd19dba633fcd9)