Add the ability to Skip SNI and Certificate configuration

**Feature Request:** Add the Ability to Skip SNI and Certificate Configuration

**Description:**
Currently, decK provides the --skip flag options to exclude specific entities such as CA certificates from the sync process. However, it would be beneficial to have an option that allows skipping both SNI and Certificate configurations. This feature would streamline workflows where SNI and Certificate management are handled separately and when it comes to DCGW configurations.

Start by tracing the existing --skip option through decK's sync entry point and its handling of SNI and Certificate entities. Check the related command help and tests, if available, to determine how a combined skip option should be exposed and verified; done means sync can omit both configurations while preserving other entity synchronization.

Written by the indexing model from the issue text.