Jetpacks (#9023)

* Movement acceleration

* tweaks

* Weightless refactor coz fuck it

* CCVars

* weightless movement tweaks

* Some cleanup while I'm here

* dorkpacks

* thanks fork

* fixes

* zoomies

* toggles

* hmm

* yamls

* b

* so true

* Effects refactor

* namespace

* review

Content.Server/Ghost/GhostSystem.cs

@@ -11,7 +11,7 @@ using Content.Shared.Examine;
 using Content.Shared.Follower;
 using Content.Shared.Ghost;
 using Content.Shared.MobState.Components;
-using Content.Shared.Movement.EntitySystems;
+using Content.Shared.Movement.Events;
 using JetBrains.Annotations;
 using Robust.Server.GameObjects;
 using Robust.Server.Player;