Upgrade from Smarty 3 to Smarty 4 to be PHP 8.1 compatible

Remove all Smarty4 dedicated tests, all are done in the same test file
like before

www/lib/smarty-4.1.0/docs/designers/chapter-debugging-console.md

@@ -0,0 +1,41 @@
+Debugging Console {#chapter.debugging.console}
+=================
+
+There is a debugging console included with Smarty. The console informs
+you of all the [included](./language-builtin-functions/language-function-include.md) templates,
+[assigned](../programmers/api-functions/api-assign.md) variables and
+[config](./language-variables/language-config-variables.md) file variables for the current
+invocation of the template. A template file named `debug.tpl` is
+included with the distribution of Smarty which controls the formatting
+of the console.
+
+Set [`$debugging`](../programmers/api-variables/variable-debugging.md) to TRUE in Smarty, and if needed
+set [`$debug_tpl`](../programmers/api-variables/variable-debug-template.md) to the template resource
+path to `debug.tpl` (this is in [`SMARTY_DIR`](../programmers/smarty-constants.md) by
+default). When you load the page, a Javascript console window will pop
+up and give you the names of all the included templates and assigned
+variables for the current page.
+
+To see the available variables for a particular template, see the
+[`{debug}`](./language-builtin-functions/language-function-debug.md) template function. To disable the
+debugging console, set [`$debugging`](../programmers/api-variables/variable-debugging.md) to FALSE. You
+can also temporarily turn on the debugging console by putting
+`SMARTY_DEBUG` in the URL if you enable this option with
+[`$debugging_ctrl`](../programmers/api-variables/variable-debugging-ctrl.md).
+
+> **Note**
+>
+> The debugging console does not work when you use the
+> [`fetch()`](../programmers/api-functions/api-fetch.md) API, only when using
+> [`display()`](../programmers/api-functions/api-display.md). It is a set of javascript statements
+> added to the very bottom of the generated template. If you do not like
+> javascript, you can edit the `debug.tpl` template to format the output
+> however you like. Debug data is not cached and `debug.tpl` info is not
+> included in the output of the debug console.
+
+> **Note**
+>
+> The load times of each template and config file are in seconds, or
+> fractions thereof.
+
+See also [troubleshooting](../appendixes/troubleshooting.md).