balg02: Mount efi partition; expose balg02 function

* .guix/guix-na/config/balg02.scm: New function: balg02; this is necessary as the efi
partition UUID changes between testing and the deployed system. Additionally, mount the efi
partition.

Its useful to note that when testing, I found a bug in guix that resulting in a partial
system upgrade! Namely, grub/kernel stuff appears to have been updated, but the `guix system
reconfigure ...` never completed. This was because the efi system partition was not mounted.
However the odd part was that even if I manually mounted the efi partition and retried `guix
system reconfigure ..` the command update would still hang. I suspect this is because for
some reason the efi system partition must be explicitly specified in the operating-system configuration.

.guix/guix-na/config/balg02.scm

@@ -27,11 +27,11 @@
   #:use-module (gnu services networking)
   #:use-module (gnu services ssh)
   #:use-module (gnu services web)
-  #:export (%system))
+  #:export (balg02 %system))
 
 (define %automation-user "auto")
 
-(define %system
+(define (balg02 efi-boot-uuid)
   (operating-system
    (host-name "balg02")
    (timezone "US/Central")
@@ -60,7 +60,11 @@
                          (device (file-system-label "root"))
                          (mount-point "/swap")
                          (type "btrfs")
-                         (options "subvol=@swap")))
+                         (options "subvol=@swap"))
+                        (file-system
+                         (device (uuid efi-boot-uuid 'fat))
+                         (mount-point "/boot/efi")
+                         (type "vfat")))
                   %base-file-systems))
 
    (swap-devices
@@ -121,3 +125,5 @@
                       (name-servers '("216.37.64.2" "216.37.64.3")))))
       (service ntp-service-type))
       %base-services))))
+
+(define %system (balg02 "3AF8-9E67"))