"disable scripts" in script manager needs update for 5.6

Description
The disable scripts button in the scripts module renames <config_dir>/luarc to luarc.disabled (the disable_scripts button callback in tools/script_manager.lua). This worked before the scripts were bundled, when darktable used <config_dir>/luarc as the Lua entry point.

Since 5.6, darktable loads the bundled luarc, which calls require "tools/script_manager" regardless of config_dir/luarc existing or not. Renaming config_dir/luarc no longer disables the scripts. It only prevents the user's own config_dir/luarc from being re-run. The bundled scripts still load and start.

Steps to reproduce

use darktable 5.6 with bundled scripts.
scripts module / action: install/update scripts / enable "disable scripts" button / click disable scripts.
observe luarc being renamed in the config dir

Restart darktable.

Expected: the Lua scripts are disabled.
Observed: bundled scripts still load and run.

Possible fixes
The current way to disable the scripts is the disable Lua scripts preference.
a) have the button toggle the disable_scripts preference (with the checkbox as the re-enable path)
b) remove the button in favour of the preference

I'd favour the latter - then enabling/disabling lua scripts is reduced to the preferences.

Inizia in tools/script_manager.lua, nel callback del pulsante disable_scripts, quindi esamina la preferenza per disabilitare gli script Lua e il percorso di caricamento della luarc inclusa in darktable 5.6. Riproduci il comportamento con gli script inclusi abilitati e determina se il pulsante debba essere rimosso oppure debba attivare/disattivare la preferenza. Il lavoro è completato quando la disabilitazione degli script tramite il modulo degli script impedisce effettivamente il caricamento degli script inclusi, lasciando comunque chiaro il percorso per riabilitarli.