docu(schema): update docs and examples to compact dict keys

vars_baremetal_example.yml

@@ -28,17 +28,18 @@ system:
   user:
     name: "admin"
     password: "CHANGE_ME"
-    public_key: "ssh-ed25519 AAAA..."
+    key: "ssh-ed25519 AAAA..."
   root:
     password: "CHANGE_ME"
   luks:
     enabled: true
     passphrase: "CHANGE_ME"
-    mapper_name: "SYSTEM_DECRYPTED"
-    auto_decrypt: true
-    auto_decrypt_method: "tpm2"
-    tpm2_device: "auto"
-    tpm2_pcrs: "7"
+    mapper: "SYSTEM_DECRYPTED"
+    auto: true
+    method: "tpm2"
+    tpm2:
+      device: "auto"
+      pcrs: "7"
   features:
     cis:
       enabled: false