feat: Allow file and directory creation modes to be configured

The defaults remain the same as before.
For now, the config options are global instead of per-user.
Note also that the BoltDB creation maintains the old default mode of 0640
since it's not really a user-facing filesystem manipulation.
Fixes #5316, #5200

cmd/config_init.go

@@ -43,6 +43,8 @@ override the options.`,
 				Theme:                 mustGetString(flags, "branding.theme"),
 				Files:                 mustGetString(flags, "branding.files"),
 			},
+			FileMode: mustGetMode(flags, "file-mode"),
+			DirMode:  mustGetMode(flags, "dir-mode"),
 		}
 
 		ser := &settings.Server{