Enable and disable the DHCP server via API

### 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

Happy New Year to everyone :-)
I have two AdGuardHome instances that maintain redundant DNS functionality via keepalived. One instance has an active DHCP server. Is it possible to activate the backup DHCP server via API in the event of a failure of the active instance?
Perhaps something like this

`curl -k -s -X POST “http://localhost:3000/control/dhcp/enable” -u user:pwd`

Or is there already another way to do this?

### Proposed solution

`curl -k -s -X POST “http://localhost:3000/control/dhcp/enable” -u user:pwd`

### Alternatives considered and additional information

_No response_