[feature] Allow device metric API view to receive compressed data

[nemesifier]

We could accept gzip compressed data in the payload or a different lighter format like messagepack.
The problem with Gzip is that we would have to implement logic to protect the system from zip bomb attacks.
The problem with messagepack is that we'd have to add another dependency to not only the server but also the OpenWrt agent, but we could solve this by making this optional.

I will leave this here as an idea for now, we will come back to it later on if there's more consensus on the next steps.