web proxy: lock down caching completely if set to off

PR: https://forum.opnsense.org/index.php?topic=4152.0

src/opnsense/service/templates/OPNsense/Proxy/squid.conf

@@ -264,7 +264,7 @@ icap_enable off
 
 {% include "OPNsense/Proxy/squid.user.post_auth.conf" ignore missing with context %}
 
-{% if helpers.exists('OPNsense.proxy.general.cache.local')  %}
+{% if helpers.exists('OPNsense.proxy.general.cache.local') and OPNsense.proxy.general.cache.local.enabled == '1' %}
 cache_mem {{ OPNsense.proxy.general.cache.local.cache_mem|default('256') }} MB
 {%  if OPNsense.proxy.general.cache.local.maximum_object_size|default('') != '' %}
 maximum_object_size {{OPNsense.proxy.general.cache.local.maximum_object_size}} MB
@@ -272,10 +272,10 @@ maximum_object_size {{OPNsense.proxy.general.cache.local.maximum_object_size}} M
 cache_replacement_policy heap LFUDA
 {%   endif %}
 {%  endif %}
-{%  if OPNsense.proxy.general.cache.local.enabled == '1' %}
-# Uncomment and adjust the following to add a disk cache directory.
 cache_dir ufs {{OPNsense.proxy.general.cache.local.directory}} {{OPNsense.proxy.general.cache.local.size}} {{OPNsense.proxy.general.cache.local.l1}} {{OPNsense.proxy.general.cache.local.l2}}
-{%  endif %}
+{% else %}
+cache deny all
+cache_mem 0
 {% endif %}
 
 # Leave coredumps in the first cache dir