Let `spo storageentity` commands reference the tenant app catalog by default

[milanholemans]

Currently, we have 4 spo storageentity commands like spo storageentity set. All these commands have a required option appCatalogUrl. While this makes sense when you want to target a site collection app catalog, it would be more user-friendly if this option were made optional. The idea is that when the option is not specified, we target the tenant app catalog by default.