Implement dynamic TimeoutStartSec filter for domains and update roles

- Added new filter plugin 'timeout_start_sec_for_domains' to calculate TimeoutStartSec based on number of domains.
- Updated sys-ctl-hlth-csp and sys-ctl-hlth-webserver tasks to use the filter.
- Removed obsolete systemctl.service.j2 in sys-ctl-hlth-csp.
- Adjusted variable naming (CURRENT_PLAY_DOMAINS_ALL etc.) in multiple roles.
- Updated srv-letsencrypt and sys-svc-certs to use uppercase vars.
- Switched pretix role to sys-stk-full-stateful and removed leftover javascript.js.
- Added unittests for the new filter under tests/unit/filter_plugins.

See conversation: https://chatgpt.com/share/68b1ae9a-1ac0-800f-b49d-2915386a1a23

roles/web-app-pretix/tasks/main.yml

@@ -1,7 +1,7 @@
 ---
 - block:
-  - name: "load docker and db for {{ application_id }}"
+  - name: "load docker, db and proxy for {{ application_id }}"
     include_role: 
-      name: sys-stk-back-stateful
+      name: sys-stk-full-stateful
   - include_tasks: utils/run_once.yml
   when: run_once_web_app_pretix is not defined