AdGuard Service Bypass or Fail Open

### Prerequisites

- [X] I have checked the [Wiki](https://github.com/AdguardTeam/AdGuardHome/wiki) and [Discussions](https://github.com/AdguardTeam/AdGuardHome/discussions) and found no answer

- [X] I have searched other issues and found no duplicates

- [X] I want to request a feature or enhancement and not ask a question

### The problem

When using the AdGuard browsing security and/or parental control features if the external internet connectivity to the submission service fails the domain resolution will also fail. This is problematic though when dealing with internal domain names that should never be filtered by these controls.

### Proposed solution

Addition of a field to exclude specified domains from the external service checks which would allow local domains to continue normal function in the event of an internet outage.

### Alternatives considered and additional information

Alternately, an option to toggle a fail-open/fail-closed in the event that external service response fails.