get that crap outta here (completely rewrites inventorysystem) (#5807)

* some work

* equip: done
unequip: todo

* unequipping done & refactored events

* workin

* movin

* reee namespaces

* stun

* mobstate

* fixes

* some work on events

* removes serverside itemcomp & misc fixes

* work

* smol merge fix

* ports template to prototype & finishes ui

* moves relay & adds containerenumerator

* actions & cuffs

* my god what is actioncode

* more fixes

* im loosing my grasp on reality

* more fixes

* more work

* explosions

* yes

* more work

* more fixes

* merge master & misc fixed because i forgot to commit before merging master

* more fixes

* fixes

* moar

* more work

* moar fixes

* suffixmap

* more work on client

* motivation low

* no. no containers

* mirroring client to server

* fixes

* move serverinvcomp

* serverinventorycomponent is dead

* gaming

* only strippable & ai left...

* only ai and richtext left

* fixes ai

* fixes

* fixes sprite layers

* more fixes

* resolves optional

* yes

* stable™️

* fixes

* moar fixes

* moar

* fix some tests

* lmao

* no comment

* good to merge™️

* fixes build but for real

* adresses some reviews

* adresses some more reviews

* nullables, yo

* fixes lobbyscreen

* timid refactor to differentiate actor & target

* adresses more reviews

* more

* my god what a mess

* removed the rest of duplicates

* removed duplicate slotflags and renamed shoes to feet

* removes another unused one

* yes

* fixes lobby & makes tryunequip return unequipped item

* fixes

* some funny renames

* fixes

* misc improvements to attemptevents

* fixes

* merge fixes

Co-authored-by: Paul Ritter <ritter.paul1@gmail.com>

Content.Server/Power/SetBatteryPercentCommand.cs

@@ -1,6 +1,5 @@
 using Content.Server.Administration;
 using Content.Server.Power.Components;
-using Content.Server.Items;
 using Content.Shared.Administration;
 using Robust.Shared.Console;
 using Robust.Shared.GameObjects;