(proxy) add transparant proxy option to squid including a template for the firewall_nat rules to forward traffic to it

(legacy) add legacy_html_escape_form_data to legacy helper functions to escape array items recursive

(legacy) it feels kind of duplicate, but to avoid too much changes on how it works now let's keep the behavior approx. the same. (part 2)

Had to merge and squash and edit punctuation:

" :" to ":", " ?" to "?" to retain original document style

PHP Fatal error:  Call to undefined function system_hosts_generate() in /usr/local/etc/inc/interfaces.inc on line 3129

(legacy) fix PHP Fatal error:  Call to undefined function create_gateway_quality_rrd() in /usr/local/etc/inc/gwlb.inc on line 330

setup_gateways_monitor needs rrd.inc

(legacy) fix PHP Fatal error:  Call to undefined function lock() in /usr/local/etc/inc/system.inc on line 125

traceback missing library issue, search function where lock() is used in line 125 (system_resolvconf_generate), then check use and add
missing library,

grep -r system_resolvconf_generate * | sed 's/:/ /g' | awk '{print $1;}' | sort -u