Add support for FlashStart Pro Plus filtering

[cotosso]

Description
Enable support for the FlashStart Pro Plus filter, allowing the use of multiple profiles up to 5 different profiles. Profiles are assigned directly in the FlashStart panel based on firewall objects or users from a connected Active Directory (AD) server.

Why
The FlashStart Pro Plus filter provides advanced content filtering capabilities. Adding support for multiple profiles enhances flexibility, enabling administrators to apply different filtering policies based on network segmentation or user identity.

Proposed Solution

Extend dnsdist implementation to satisfy these new requirements.
Define multiple profiles on dnsdist, each one with 2 dedicated DNS servers.
Each profile is linked to a specific ipset or nftset which contains the IP addresses of the clients that use it.

• Clients are dinamically assigned to their specific ipset/nfset exclusively within the FlashStart panel based on:
  • Firewall objects (host sets)
  • Users authenticated via an AD server

The default profile is for clients who have not been assigned to any specific profile.