plugins: make the autoclean plugin static

The autocleaning will only happen if the autocleaninvoice-cycle startup
option is passed, which cannot happen if the plugin is started
post-startup.
Thus, it's less misleading for users to restrict its usage to startup.

Changelog-Added: plugins: The `autoclean` plugin is now static (you cannot manage it with the `plugin` RPC command anymore).

Signed-off-by: Antoine Poinsot <darosior@protonmail.com>

plugins/autoclean.c

@@ -88,7 +88,7 @@ static const struct plugin_command commands[] = { {
 int main(int argc, char *argv[])
 {
 	setup_locale();
-	plugin_main(argv, init, PLUGIN_RESTARTABLE, NULL, commands, ARRAY_SIZE(commands),
+	plugin_main(argv, init, PLUGIN_STATIC, NULL, commands, ARRAY_SIZE(commands),
 	            NULL, 0, NULL, 0,
 		    plugin_option("autocleaninvoice-cycle",
 				  "string",