rc: load vital modules on kernel boot

src/etc/rc.loader.d/20-modules

+# Vital modules that are not in FreeBSD generic
+# will be loaded on boot, which makes races with
+# settings impossible as the kernel boots up
+# in a consistent way as it looks like all the
+# modules were compiled into the kernel.
 carp_load="YES"
 if_bridge_load="YES"
+if_enc_load="YES"
+if_gif_load="YES"
+if_gre_load="YES"
+if_lagg_load="YES"
+if_sft_load="YES"
+if_tap_load="YES"
+if_tun_load="YES"
+if_vlan_load="YES"
+pf_load="YES"
+pflog_load="YES"
+pfsync_load="YES"
 # The netgraph(4) framework is loaded here
 # for backwards compat with the pre-16.7
 # kernel configuration that compiled all of