roles/logrotate: Install and enable logrotate

Since Apache HTTPD does not have any built-in log rotation capability,
we need `logrotate`.  Somewhere along the line, the *logrotate* package
stopped being installed by default.  Additionally, with Fedora 30, it
changed from including a drop-in file for (Ana)cron to providing a
systemd timer unit.

The *logrotate* role will ensure that the *logrotate* package is
installed, and that the *logrotate.timer* service is enabled and
running.  This in turn will ensure that `logrotate` runs daily.  Of
course, since the systemd units were added in Fedora 30, machines to
which this role is applied must be running at least that version.

By listing the *logrotate* role as a dependency of the *httpd* role, we
can ensure that `logrotate` manages the Apache error and access log
files on any server that runs Apache HTTPD.

roles/apache/meta/main.yml

@@ -0,0 +1,4 @@
+dependencies:
+- role: logrotate
+  tags:
+  - logrotate

roles/logrotate/tasks/main.yml

@@ -0,0 +1,19 @@
+- name: ensure logrotate is installed
+  package:
+    name: logrotate
+    state: present
+  tags:
+  - install
+
+- name: ensure logrotate timer unit is enabled
+  systemd:
+    name: logrotate.timer
+    enabled: true
+  tags:
+  - service
+- name: ensure logrotate timer unit is started
+  systemd:
+    name: logrotate.timer
+    state: started
+  tags:
+  - service