Merge branch 'grat' into 'master'

[nancy/grat] Set uefi configuration for grat

See merge request !436

data/grid5000/sites/nancy/clusters/grat/grat.json

 {
-  "boot_type": "bios",
+  "boot_type": "uefi",
   "created_at": "Wed, 07 Sep 2022 00:00:00 GMT",
   "exotic": false,
   "kavlan": false,

input/grid5000/sites/nancy/clusters/grat/grat.yaml

 model: HPe Apollo 6500
 created_at: 2022-09-07
 kavlan: false
-boot_type: bios 
+boot_type: uefi
 exotic: false
 queues:
   - admin