users: rip out the legacy ssh tunnel shell

Shell access is sufficient, I see absolutely no value in this.

src/etc/inc/auth.inc

@@ -416,8 +416,6 @@ function local_user_set(&$user)
 		$user_shell = '/bin/csh';
 	} elseif (userHasPrivilege($user, 'user-copy-files')) {
 		$user_shell = '/usr/local/bin/scponly';
-	} elseif (userHasPrivilege($user, 'user-ssh-tunnel')) {
-		$user_shell = '/usr/local/sbin/ssh_tunnel_shell';
 	}
 
 	/* unlock valid shell users */

src/opnsense/mvc/app/models/OPNsense/Core/ACL_Legacy_Page_Map.json

@@ -15,10 +15,6 @@
         "name": "User - System - Shell account access",
         "descr": "Indicates whether the user is able to login for example via SSH."
     },
-    "user-ssh-tunnel": {
-        "name": "User - System - SSH tunneling",
-        "descr": "Indicates whether the user is able to login for tunneling via SSH when they have no shell access. Note: User - System - Copy files conflicts with this privilege."
-    },
     "user-ipsec-xauth-dialin": {
         "name": "User - VPN - IPsec xauth Dialin",
         "descr": "Indicates whether the user is allowed to dial in via IPsec xauth (Note: Does not allow shell access, but may allow the user to create ssh tunnels)"