Singularity beacon fix and clean-up

__Content :__

* Fixes singularity beacon deactivating when splitting powernets (a.k.a cutting a cable somewhere on the powernet).
Thanks MrStonedOne for reporting.
* Made the beacon a power machinery, instead of having its own set of proc (exception is power usage, as we want stealth comsumption).
* The beacon now consumes 1500W instead of just checking if the powernet has this much.
* Removed/added to processing list when inactive/active, instead of constantly processing it.