Introduce option to sequential refreshing of block lists (for low mem devices)

### 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 use AdGuard Home as a container on the Mikrotik hAP ax3 device. The device has only 1 GB of RAM, of which ~600 MB is available for the container. AdGuard Home causes OOM and reboots the device upon refreshing the block lists. This is becoming more and more of a problem when I use more block lists. When gone through multiple reboots, it works fine, leaving 320 MB of memory available. So it seems memory pressure is only occurring when filters are updating.

### Proposed solution

From what it seems, AdGuard Home downloads multiple (maybe all?) lists concurrently and updates them at the same time.

I would like to have an option to set AdGuard Home to update block lists sequentially, one by one, in order to conserve memory and not cause OOM and kernel panic.

I don't care if the update process takes 1 minute or 10. I just want my device to be stable. The OOM condition causes the entire router to reboot, thus stopping all traffic until it gets back.

Thanks in advance.

### Alternatives considered and additional information

I might resign from some lists, but that's not the solution I'd prefer...