Provisioning support

### 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'd like to automate AdGuard Home deployment via Docker Compose by providing a pre-configured `AdGuardHome.yaml' file, skipping the currently required initial UI setup on port 3000.

### Proposed solution

If the configuration file already exists there or somewhere else (separate provisioning folder or whatnot), use it and skip the initial UI config.

### Alternatives considered and additional information

#7577 asks for the same feature.