Update license

This drops COPYING.Exceptions which has been moved with icinga/icinga2#6283

refs icinga/icinga2#6215

Fix permission issues on SUSE distributions

Fix regression in include file list

The icinga/cmd file was moved from the bin package to common.

The issue was introduced by the commit 900b7cf3

The preceding attr was marking not only the directory but also the files
as executable.

Fix issues and improve spec for SLE submit request

https://spdx.org/licenses/

* Add Provides tag for user and groups

Following the guide https://en.opensuse.org/openSUSE:Packaging_guidelines#Users_and_Groups
as requested by our security team.

refs #6

Following this commit
https://github.com/Icinga/icinga2/commit/4970c459ee9fa09c4ab92a2553824f2586fb77f5
logrotate needs to be available during build for the correct
configuration to be installed.

Builds needed for:
* SLES 12
* Fedora 27

* Improve RPM groups
* Improve grammar in RPM subpackage descriptions
* Remove redundant %clean section from rpm spec
* Fix service.d dir which was not referenced by any package
* Use sle_version instead of deprecated leap_version
  see https://en.opensuse.org/openSUSE:Build_Service_cross_distribution_howto#leap_version_macro_.28deprecated.29
* Also add systemd limits file to openSUSE Tumbleweed
* Documentation should not hard-require the program
  as it is technically "usable" without it.

Dropping policyhelp for Fedora 27, was only needed on Fedora < 20, and EL < 7

See https://fedoraproject.org/wiki/SELinux_Policy_Modules_Packaging_Draft