Devtools: PM4 Explorer (#1094)

* Devtools: Pause system

* Devtools: pm4 viewer

- new menu bar
- refactored video_info layer
- dump & inspect pm4 packets
- removed dumpPM4 config
- renamed System to DebugState
- add docking space
- simple video info constrained to window size

* Devtools: pm4 viewer - add combo to select the queue

* Devtools: pm4 viewer - add hex editor

* Devtools: pm4 viewer - dump current cmd

* add monospaced font to devtools

* Devtools: pm4 viewer - use spec op name

avoid some allocations

src/core/linker.cpp

@@ -18,6 +18,7 @@
 #include "core/memory.h"
 #include "core/tls.h"
 #include "core/virtual_memory.h"
+#include "debug_state.h"
 
 namespace Core {
 
@@ -88,6 +89,7 @@ void Linker::Execute() {
 
     // Init primary thread.
     Common::SetCurrentThreadName("GAME_MainThread");
+    DebugState.AddCurrentThreadToGuestList();
     Libraries::Kernel::pthreadInitSelfMainThread();
     EnsureThreadInitialized(true);