feat(pfsense_rule): add state tracking options

[adriangalilea]

Summary

Adds support for PF state tracking advanced options to the pfsense_rule module. These fields were previously listed in RULE_UNMANAGED_ELEMENTS (preserved but not configurable). This PR promotes them to fully managed parameters.

New parameters

Parameter	XML element	Description
max_src_conn	max-src-conn	Max established connections per source host
max_src_states	max-src-states	Max state entries per source host
max_src_nodes	max-src-nodes	Max unique source hosts
max_src_conn_rate	max-src-conn-rate	Max new connections per time interval
max_src_conn_rates	max-src-conn-rates	Time interval (seconds) for max_src_conn_rate
statetimeout	statetimeout	State timeout in seconds

Example usage

- name: Rate-limit inbound connections
  pfsense_rule:
    name: 'Rate-limited inbound'
    action: pass
    interface: wan
    floating: true
    direction: in
    quick: true
    protocol: tcp
    source: any
    destination: my_servers
    destination_port: 21841
    max_src_conn: 3
    max_src_states: 3
    max_src_conn_rate: 3
    max_src_conn_rates: 60
    state: present

Validation

• State tracking options only work on pass rules (pfSense requirement)
• max_src_conn and max_src_conn_rate require TCP protocol
• max_src_conn_rate and max_src_conn_rates must be set together

Motivation

The pfSense REST API package (pfSense-pkg-RESTAPI) does not expose these fields either, making Ansible via pfsensible the only programmatic way to manage PF rate-limiting rules. These options are critical for protecting services from connection floods (SYN floods, DDoS) without manual Web UI configuration.

Changes

• plugins/module_utils/rule.py: Added 6 params to RULE_ARGUMENT_SPEC, XML mapping in _params_to_obj, validation in _validate_params, removal handling, and logging
• plugins/modules/pfsense_rule.py: Added documentation and example for new params
• tests/unit/plugins/modules/test_pfsense_rule_create.py: Added 8 tests covering creation, validation, and error cases