Machines de/connecting from/to a powernet will now always call the connect_to_network/disconnect_from_network procs instead of de/connecting directly.
Fix merging powernet on turf sometimes not connecting machines.
Removed the now unused directwired variable
Only mobs will be unanchored to avoid being destroyed by shuttles

Other anchored objects, like windows, will remain.
Delegated the panels and trackers control to Solar Control Computers instead of the Sun controller.
Merge pull request #4063 from Menshin/solar_control_refactoring

Solar control refactoring
Merge pull request #4062 from Menshin/powernet_machine_connection

Powernets machines connection polishing
Merge pull request #4061 from Ikarrus/mobanchors

Only mobs will be unanchored to avoid being destroyed by shuttles
Merge pull request #4068 from Firecage/Moarbotany

Changes to botany plants
Merge branch 'master' of https://github.com/tgstation/-tg-station.git into Moarbotany