Add basic nextcloud deployment

Uses php-fpm image and is served through a simple caddy server.
Automatically deploys by default and can be automatically deployed with
smtp e-mail sending and s3 primary object storage optionally if desired.

Utilizes some necessary hackery for container ordering and startup so
startup is relatively slow (takes around 2-5 minutes at least) but once
running should be stable and uninterrupted.

Implements health-checks for all involved containers.

Switch apache for php-fpm image

roles/nextcloud/defaults/main.yml

@@ -0,0 +1,44 @@
+---
+
+# set preferred application version
+nextcloud_version: fpm-alpine
+# set preferred postgres version
+nextcloud_db_version: 12-alpine
+
+nextcloud_upstream_file_dir: "{{ docker_stack_files_dir }}/{{ stack_name }}"
+
+nextcloud_use_https: true
+
+# the subdomain link nextcloud will be reachable under
+subdomain_alias: files
+
+# the following block is required for a basic setup
+nextcloud_app_admin_username: mynextcloudusername
+nextcloud_app_admin_password: mynextcloudpassword
+nextcloud_redis_password: myredispass
+nextcloud_db_username: nextcloud
+nextcloud_db_password: secretnextcloud
+
+# if you wish to access your nextcloud instance from the reverse proxy
+nextcloud_trusted_domains: "{{ subdomain_alias }}.{{ server_domain }}"
+
+# the following block is required *fully* for working smtp
+# nextcloud_smtp_host: smtp.eu.mailgun.org
+nextcloud_smtp_secure: ssl
+nextcloud_smtp_port: 465
+nextcloud_smtp_authtype: LOGIN
+# nextcloud_smtp_username: <smtp-username>
+# nextcloud_smtp_password: <smtp-password>
+nextcloud_smtp_from_address: noreply
+nextcloud_smtp_from_domain: "{{ server_domain }}"
+
+# the following block is required *fully* for primary object storage
+# nextcloud_s3_host: s3.eu-central-1.wasabisys.com
+# nextcloud_s3_bucket: nextcloud
+# nextcloud_s3_key: <s3-key>
+# nextcloud_s3_secret: <s3-secret>
+# nextcloud_s3_port: 443
+# nextcloud_s3_ssl: true
+# nextcloud_s3_region: eu-central-1
+# nextcloud_s3_usepath_style: true
+