Implement servers locally in xtask

[MabezDev]

Context: #85 (review)

I don't think we should depend on external tools and services for this, I think we should have an xtask which the user can just launch at the start of the training which will start the required servers and collect/print anything sent to it, i.e received x temperature from MQTT/HTTP.

[bjoernQ]

Haven't thought about this but it's probably a good idea - especially for OTA the server could automagically pick up up a freshly compiled ELF and convert it into a flashable image etc. 🤔

[SergioGasquez]

I also like the idea in #85 (comment), so I guess its worth having it here so we dont forget about it