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.Shared/Inventory/InventorySystem.Relay.cs

@@ -1,7 +1,7 @@
 using Content.Shared.Damage;
 using Content.Shared.Electrocution;
 using Content.Shared.Explosion;
-using Content.Shared.Movement.EntitySystems;
+using Content.Shared.Movement.Systems;
 using Content.Shared.Slippery;
 
 namespace Content.Shared.Inventory;