Update Dota & CS2 support

[GAMMACASE]

This is currently a WIP and all the stuff could be changed until marked as ready.

PR Completion status:

• ConVar and ConCommand related stuff:
  • ICvar interface;
  • ConVar lifecycle (Creation/Operation/Deletion);
  • ConCommand lifecycle (Creation/Operation/Deletion);
• Utility classes:
  • Obsoletion of tier1.lib;
  • Transition to tier0 structure;
  • KeyValues;
  • CBufferString;
  • CUtlString;
  • CUtlVectorBase;
  • CUtlMemoryPoolBase (?);
  • CUtlMemoryFixedGrowable_Base (?);
• Schema access:
  • Datamap;
  • CSchemaClassInfo;
• Game Events:
  • IGameEvent;
  • IGameEventSystem;
  • IGameEventManager2;
• Entity access:
  • Client userid/pawn/controller/ehandle conversation;
  • CGameEntitySystem;
  • CConcreteEntityList;
  • CEntityIdentity;
  • CEntityHandle;
  • CEntityKeyValues;
  • EntityInstanceByClassIter_t;

If you have anything to add, please make sure to pr them to my initial branch as well as discuss them beforehand in the AlliedModders discord in appropriate channels.

This is a collaborative work and a lot of the research and reversing was done by: SlidyBat#4737, Poggu#5993, psychonic#9045, zer0.k#2613, Mooshua#1857, Boeing 666#1307, komashchenko, and others from the AM Discord. So huge thanks to them!

[psychonic]

Per our discussion on Discord, we will be merging this as-is for now so that MM:S builds can start going. A separate issue will be created for progress tracking.