Add screen rendering events for buttons

src/main/kotlin/moe/nea/firmament/events/HandledScreenForegroundEvent.kt

@@ -0,0 +1,10 @@
+package moe.nea.firmament.events
+
+import net.minecraft.client.gui.screen.ingame.HandledScreen
+
+data class HandledScreenForegroundEvent(
+    val screen: HandledScreen<*>,
+    val mouseX: Int, val mouseY: Int, val delta: Float
+) : FirmamentEvent() {
+    companion object : FirmamentEventBus<HandledScreenForegroundEvent>()
+}