stand/lua: always allow overriding with local config files

Loader now also read configuration files listed in local_loader_conf_files.
Files listed here are the last ones read. And /boot/loader.conf.local was
moved from loader_conf_files to local_loader_conf_files leaving only
loader.conf and device.hints in loader_conf_files by default.

The idea is to ensure local_loader_conf_files, i.e., /boot/loader.conf.local,
can always be used to override other user defined settings.

So the sequencing is now as follow:

 1. Bootstrap:
     /boot/defaults/loader.conf

 2. Read loader_conf_files files:
     /boot/device.hints
     /boot/loader.conf

 3. Read loader_conf_dirs files:
     /boot/loader.conf.d/*.conf

 4. And finally, rread local_loader_conf_files files:
     /boot/loader.conf.local

1 files changed, 21 insertions, 0 deletions

diff --git a/UPDATING b/UPDATING
index 14fae1eb0656..33bae2a42b9d 100644
--- a/UPDATING
+++ b/UPDATING
@@ -27,6 +27,27 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 15.x IS SLOW:
 	world, or to merely disable the most expensive debugging functionality
 	at runtime, run "ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20240202:
+	Loader now also read configuration files listed in local_loader_conf_files.
+	Files listed here are the last ones read. And /boot/loader.conf.local was
+	moved from loader_conf_files to local_loader_conf_files leaving only
+	loader.conf and device.hints in loader_conf_files by default.
+
+	The following sequencing is applied:
+
+	1. Bootstrap:
+	    /boot/defaults/loader.conf
+
+	2. Read loader_conf_files files:
+	    /boot/device.hints
+	    /boot/loader.conf
+
+	3. Read loader_conf_dirs files:
+	    /boot/loader.conf.d/*.conf
+
+	4. And finally, rread local_loader_conf_files files:
+	    /boot/loader.conf.local
+
 20240201:
 	sendmail 8.18.1 has been imported and merged.  This version enforces
 	stricter RFC compliance by default, especially with respect to line