New Devices cleanup #250 work

front/php/templates/language/en_us.php

@@ -541,6 +541,8 @@ The arp-scan time itself depends on the number of IP addresses to check so set t
 'SCAN_CYCLE_MINUTES_description' => 'The delay between scans in minutes. If using arp-scan, the scan time itself depends on the number of IP addresses to check. This is influenced by the network mask set in the <a href="#SCAN_SUBNETS"><code>SCAN_SUBNETS</code> setting</a> at the top. Every IP takes a couple seconds to scan.',
 'DAYS_TO_KEEP_EVENTS_name' => 'Delete events older than',
 'DAYS_TO_KEEP_EVENTS_description' => 'This is a maintenance setting. This specifies the number of days worth of event entries that will be kept. All older events will be deleted periodically. Also applies on Plugin Events History.',
+'HRS_TO_KEEP_NEWDEV_name' => 'Keep new devices for',
+'HRS_TO_KEEP_NEWDEV_description' => 'This is a maintenance setting. If enabled (<code>0</code> is disabled), Devices marked as <b>New Device</b> will be deleted if their <b>First Session</b> time was older than the specified hours in this setting. Use this setting if you want to auto-delete <b>New Devices</b> after <code>X</code> hours',
 'REPORT_DASHBOARD_URL_name' => 'Pi.Alert URL',
 'REPORT_DASHBOARD_URL_description' => 'This URL is used as the base for generating links in the emails. Enter full URL starting with <code>http://</code> including the port number (no trailig slash <code>/</code>).',
 'DIG_GET_IP_ARG_name' => 'Internet IP discovery',