roles/grafana: Deploy Grafana

This commit introduces the *grafana* role and the corresponding
`grafana.yml` playbook.  The role installs Grafana using the system
package manager, and configures the server (including LDAP
authentication).

roles/grafana/tasks/main.yml

@@ -0,0 +1,43 @@
+- name: ensure grafana is installed
+  package:
+    name: grafana
+    state: present
+  tags:
+  - install
+
+- name: ensure grafana is configured
+  template:
+    src: grafana.ini.j2
+    dest: /etc/grafana/grafana.ini
+    owner: root
+    group: grafana
+    mode: '0640'
+  notify: restart grafana
+  tags:
+  - config
+- name: ensure grafana ldap servers are configured
+  template:
+    src: ldap.toml.j2
+    dest: /etc/grafana/ldap.toml
+    owner: root
+    group: grafana
+    mode: '0640'
+  notify: restart grafana
+  tags:
+  - config
+
+- name: ensure nginx is configured to proxy for grafana
+  copy:
+    src: grafana.nginx.conf
+    dest: /etc/nginx/default.d/grafan.conf
+    mode: '0644'
+  notify: reload nginx
+  tags:
+  - nginx-config
+
+- meta: flush_handlers
+
+- name: ensure grafana is running
+  service:
+    name: grafana-server
+    state: started