[client] overlay: move keybinds and config into the overlays

This adds a new `earlyInit` call which allows the overlay to register
options before actually being intialized. Also the keybind handling and
state tracking for each overlay has been moved internal to the overlay
itself.

client/src/overlay/graphs.c

@@ -29,6 +29,7 @@
 
 struct GraphState
 {
+  bool show;
   struct ll * graphs;
 };
 
@@ -46,7 +47,7 @@ struct OverlayGraph
 
 static void configCallback(void * udata)
 {
-  igCheckbox("Show Timing Graphs", &g_state.showTiming);
+  igCheckbox("Show Timing Graphs", &gs.show);
   igSeparator();
 
   igBeginTable("split", 2, 0, (ImVec2){}, 0);
@@ -61,10 +62,18 @@ static void configCallback(void * udata)
   igEndTable();
 }
 
-static bool graphs_init(void ** udata, void * params)
+static void showTimingKeybind(int sc, void * opaque)
+{
+  gs.show ^= true;
+  app_invalidateWindow();
+}
+
+static bool graphs_init(void ** udata, const void * params)
 {
   gs.graphs = ll_new();
   app_overlayConfigRegister("Performance Metrics", configCallback, NULL);
+  app_registerKeybind(KEY_T, showTimingKeybind, NULL,
+      "Show frame timing information");
   return true;
 }
 
@@ -111,7 +120,7 @@ static bool rbCalcMetrics(int index, void * value_, void * udata_)
 static int graphs_render(void * udata, bool interactive,
     struct Rect * windowRects, int maxRects)
 {
-  if (!g_state.showTiming)
+  if (!gs.show)
     return 0;
 
   float fontSize = igGetFontSize();