refactor(luks): use system_cfg.luks directly across roles

roles/configuration/tasks/encryption/keyfile.yml

@@ -16,7 +16,7 @@
           {{
             lookup(
               'community.general.random_string',
-              length=(partitioning_luks_keyfile_size | int),
+              length=(system_cfg.luks.keysize | int),
               override_all='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
             )
           }}
@@ -71,7 +71,7 @@
               {{
                 lookup(
                   'community.general.random_string',
-                  length=(partitioning_luks_keyfile_size | int),
+                  length=(system_cfg.luks.keysize | int),
                   override_all='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
                 )
               }}