DHCP add comment field

### 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

I am currently using dnsmasq for local dhcp & dns and unbound for regular name resolution.
I have a lot of static host rules in dnsmasq with comments on usecase etc. I'd like to migrate also these comments for the static leases.

### Proposed solution

Add a comment/free text field to each static lease (as already mentioned in https://github.com/AdguardTeam/AdGuardHome/discussions/3347).

### Alternatives considered and additional information

_No response_