Refactor Nextcloud configuration to use OCC script approach and add email/OIDC support

Major architectural changes:
- Replace config file templating with unified OCC command script
- Remove custom_apps mount overlay that caused Caddy serving issues
- Implement script-based configuration for idempotency and clarity

Configuration improvements:
- Add email/SMTP support with master switch (nextcloud_email_enabled)
- Add OIDC/SSO integration with Authentik support
- Add apps installation (user_oidc, calendar, contacts)
- Enable group provisioning and quota management from OIDC
- Set nextcloud_oidc_unique_uid to false per Authentik docs

Files removed:
- nextcloud.config.php.j2 (replaced by OCC commands)
- redis.config.php.j2 (replaced by OCC commands)
- optimization.yml (merged into configure.yml)

Files added:
- configure-nextcloud.sh.j2 (single source of truth for config)
- configure.yml (deploys and runs configuration script)

Documentation:
- Add comprehensive OIDC setup guide with Authentik integration
- Document custom scope mapping and group provisioning
- Add email configuration examples for common providers
- Update vault variables documentation
- Explain two-phase deployment approach

Host configuration:
- Change admin user from 'admin' to 'joakim'
- Add admin email configuration

roles/nextcloud/tasks/configure.yml

@@ -0,0 +1,36 @@
+---
+# =================================================================
+# Nextcloud Configuration via Script
+# =================================================================
+# Rick-Infra - Nextcloud Role
+#
+# Deploys and runs a configuration script inside the Nextcloud
+# container to set system configuration via OCC commands.
+
+- name: Deploy Nextcloud configuration script
+  template:
+    src: configure-nextcloud.sh.j2
+    dest: "{{ nextcloud_config_dir }}/configure.sh"
+    mode: '0755'
+  tags: [config, nextcloud-config]
+
+- name: Run Nextcloud configuration script
+  command: podman exec --user www-data nextcloud bash /var/www/html/config/configure.sh
+  register: nc_config_result
+  changed_when: false  # Script output doesn't indicate changes reliably
+  failed_when: nc_config_result.rc != 0
+  tags: [config, nextcloud-config]
+
+- name: Display configuration script output
+  debug:
+    msg: "{{ nc_config_result.stdout_lines }}"
+  when: nc_config_result.stdout | length > 0
+  tags: [config, nextcloud-config]
+
+- name: Display configuration script errors
+  debug:
+    msg: "{{ nc_config_result.stderr_lines }}"
+  when: 
+    - nc_config_result.stderr | length > 0
+    - nc_config_result.rc != 0
+  tags: [config, nextcloud-config]