Replace yum config manager with dnf alternative

We need config-manager to enable repositories for CentOS 8 hosts.

Also, since we do need PowerTools inside lxc containers, we should
install tooling not only for bare metal, but also for containers.
Some projects, like manila, also require some packages out of
PowerTools repository.

Change-Id: Ic150c2698acc3b78a60de36b4714fe2aafa3e970

defaults/main.yml

@@ -151,6 +151,7 @@ openstack_hosts_centos_mirror_url: 'http://mirror.centos.org/centos'
 openstack_hosts_rdo_mirror_url: 'https://trunk.rdoproject.org'
 openstack_hosts_rdo_repo_url: "{{ openstack_hosts_rdo_mirror_url }}/centos{{ ansible_distribution_major_version }}-master/current-passed-ci/"
 openstack_hosts_rdo_deps_url: "{{ openstack_hosts_rdo_mirror_url }}/centos{{ ansible_distribution_major_version }}-master/deps/latest/"
+openstack_hosts_power_tool_enable: "{{ ('manila_all' in groups or 'gnocchi_all' in groups or install_method | default('source') == 'distro') }}"
 
 # Default opensuse mirrors URLs
 opensuse_mirror: "http://download.opensuse.org"

tasks/openstack_hosts_configure_dnf.yml

@@ -102,10 +102,10 @@
     - install_method == 'distro'
 
 - name: Enable PowerTools repository
-  command: yum-config-manager --enable PowerTools
+  command: dnf config-manager --set-enabled PowerTools
   changed_when: false
   when:
-    - install_method == 'distro'
+    - openstack_hosts_power_tool_enable | bool
 
 - name: Enable/Disable module_hotfixes
   lineinfile:

vars/redhat-8.yml

@@ -73,7 +73,6 @@ _openstack_host_metal_distro_packages:
   - sudo
   - time
   - wget
-  - yum-utils
 
 _package_repos_keys:
   - name: openstack-queens
@@ -84,6 +83,8 @@ _package_repos_keys:
     keyfile: "gpg/61E8806C"
 
 _package_list:
+  - name: dnf-plugins-core
+    state: present
   - name: epel-release
     state: absent
   - name: "centos-openstack-release-*"