Add option to allow empty password or not (closes #577)

Signed-off-by: AnErrupTion <anerruption@disroot.org>

src/config/Lang.zig

@@ -15,6 +15,7 @@ err_config: []const u8 = "unable to parse config file",
 err_console_dev: []const u8 = "failed to access console",
 err_dgn_oob: []const u8 = "log message",
 err_domain: []const u8 = "invalid domain",
+err_empty_password: []const u8 = "empty password not allowed",
 err_envlist: []const u8 = "failed to get envlist",
 err_hostname: []const u8 = "failed to get hostname",
 err_mlock: []const u8 = "failed to lock password memory",