Enable/Disable Templates

### The required feature described as a wish

After working more extensively with ACS, I’ve noticed several missing features that are necessary for effective template management.

When uploading a modified version of an existing template (for example, Rocky9), we are forced to give it a new name rather than following our established naming scheme, in order to avoid confusion with the old version. We also cannot simply delete the old template, as it is already in use by multiple production instances.

As a result, an Enable/Disable feature is needed. This would allow older templates to be disabled while keeping updated or approved templates active. Existing instances would continue running on the old templates, while new instances would be created using the enabled, updated ones.

Non vengono indicati file, test o punti di ingresso; inizia tracciando i flussi di caricamento dei template ACS e di creazione delle istanze. Definisci e verifica il comportamento di abilitazione/disabilitazione, in modo che le istanze esistenti mantengano i propri template e le nuove istanze selezionino solo i template abilitati.

Scritto dal modello di indicizzazione a partire dal testo della issue.