nextcloud: Deploy Nextcloud w/ Apache+PHP-FPM

The *nextcloud* role installs Nextcloud from the specified release
archive, downloading it to the control machine first if necessary, and
configures Apache and PHP-FPM to serve it.

The `nextcloud.yml` playbook uses the *cert* role to install the X.509
certificate for the Nextcloud server, sets up Apache HTTPD with the
*apache* role, and installs Nextcloud using the *nextcloud* role.

The host *cloud0.pyrocufflink.blue* is the Nextcloud server for
Pyrocufflink.

roles/nextcloud/handlers/main.yml

@@ -0,0 +1,12 @@
+- name: reload httpd
+  service:
+    name: httpd
+    state: reloaded
+- name: upgrade nextcloud
+  become: true
+  become_user: apache
+  command: php /var/www/html/occ upgrade
+- name: update nextcloud .htaccess
+  become: true
+  become_user: apache
+  command: php /var/www/html/occ maintenance:update:htaccess