Implement filter checks: ensure all defined filters are used and remove dead code

Integration tests added/updated:
- tests/integration/test_filters_usage.py: AST-based detection of filter definitions (FilterModule.filters), robust Jinja detection ({{ ... }}, {% ... %}, {% filter ... %}), plus Python call tracking; fails if a filter is used only under tests/.
- tests/integration/test_filters_are_defined.py: inverse check — every filter used in .yml/.yaml/.j2/.jinja2/.tmpl must be defined locally. Scans only inside Jinja blocks and ignores pipes inside strings (e.g., lookup('pipe', "... | grep ... | awk ...")) to avoid false positives like trusted_hosts, woff/woff2, etc.

Bug fixes & robustness:
- Build regexes without %-string formatting to avoid ValueError from literal '%' in Jinja tags.
- Strip quoted strings in usage analysis so sed/grep/awk pipes are not miscounted as filters.
- Prevent self-matches in the defining file.

Cleanup / removal of dead code:
- Removed unused filter plugins and related unit tests:
  * filter_plugins/alias_domains_map.py
  * filter_plugins/get_application_id.py
  * filter_plugins/load_configuration.py
  * filter_plugins/safe.py
  * filter_plugins/safe_join.py
  * roles/svc-db-openldap/filter_plugins/build_ldap_nested_group_entries.py
  * roles/sys-ctl-bkp-docker-2-loc/filter_plugins/dict_to_cli_args.py
  * corresponding tests under tests/unit/*
- roles/svc-db-postgres/filter_plugins/split_postgres_connections.py: dropped no-longer-needed list_postgres_roles API; adjusted tests.

Misc:
- sys-stk-front-proxy/defaults/main.yml: clarified valid vhost_flavour values (comma-separated).

Ref: https://chatgpt.com/share/68b56bac-c4f8-800f-aeef-6708dbb44199

roles/svc-db-openldap/filter_plugins/build_ldap_nested_group_entries.py

@@ -1,77 +0,0 @@
-def build_ldap_nested_group_entries(applications, users, ldap):
-    """
-    Builds structured LDAP role entries using the global `ldap` configuration.
-    Supports objectClasses: posixGroup (adds gidNumber, memberUid), groupOfNames (adds member).
-    Now nests roles under an application-level OU: application-id/role.
-    """
-
-    result = {}
-
-    # Base DN components
-    role_dn_base = ldap["DN"]["OU"]["ROLES"]
-    user_dn_base = ldap["DN"]["OU"]["USERS"]
-    ldap_user_attr = ldap["USER"]["ATTRIBUTES"]["ID"]
-
-    # Supported objectClass flavors
-    flavors = ldap.get("RBAC").get("FLAVORS")
-
-    for application_id, app_config in applications.items():
-        # Compute the DN for the application-level OU
-        app_ou_dn = f"ou={application_id},{role_dn_base}"
-
-        ou_entry = {
-            "dn": app_ou_dn,
-            "objectClass": ["top", "organizationalUnit"],
-            "ou": application_id,
-            "description": f"Roles for application {application_id}" 
-        }
-        result[app_ou_dn] = ou_entry
-
-        # Standard roles with an extra 'administrator'
-        base_roles = app_config.get("rbac", {}).get("roles", {})
-        roles = {
-            **base_roles,
-            "administrator": {
-                "description": "Has full administrative access: manage themes, plugins, settings, and users"
-            }
-        }
-
-        group_id = app_config.get("group_id")
-
-        for role_name, role_conf in roles.items():
-            # Build CN under the application OU
-            cn = role_name
-            dn = f"cn={cn},{app_ou_dn}"
-
-            entry = {
-                "dn": dn,
-                "cn": cn,
-                "description": role_conf.get("description", ""),
-                "objectClass": ["top"] + flavors,
-            }
-
-            member_dns = []
-            member_uids = []
-            for username, user_conf in users.items():
-                if role_name in user_conf.get("roles", []):
-                    member_dns.append(f"{ldap_user_attr}={username},{user_dn_base}")
-                    member_uids.append(username)
-
-            if "posixGroup" in flavors:
-                entry["gidNumber"] = group_id
-                if member_uids:
-                    entry["memberUid"] = member_uids
-
-            if "groupOfNames" in flavors and member_dns:
-                entry["member"] = member_dns
-
-            result[dn] = entry
-
-    return result
-
-
-class FilterModule(object):
-    def filters(self):
-        return {
-            "build_ldap_nested_group_entries": build_ldap_nested_group_entries
-        }