[Vulkan] Add tesselation support

Pretty much just following the D3D12 implementation

src/xenia/gpu/shaders/discrete_triangle_1cp.hs.glsl

@@ -0,0 +1,44 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2025. All rights reserved.                                       *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#version 460
+#extension GL_GOOGLE_include_directive : require
+
+// Tessellation control shader for discrete triangle tessellation with 1 control
+// point (patch indexed).
+
+layout(vertices = 1) out;
+
+#include "xenos_draw.glsli"
+
+// Input from vertex shader - vertex index as float.
+layout(location = 0) in float in_index[];
+
+// Output to tessellation evaluation shader - vertex index as float.
+layout(location = 0) out float out_index[];
+
+void main() {
+  // Pass through the vertex index.
+  out_index[gl_InvocationID] = in_index[gl_InvocationID];
+
+  // Set tessellation levels (only one invocation for 1cp).
+  // Xenos creates a uniform grid for triangles, but this can't be reproduced
+  // using the tessellator on the PC, so just use what has the closest level
+  // of detail.
+  // https://www.slideshare.net/blackdevilvikas/next-generation-graphics-programming-on-xbox-360
+  //
+  // 1.0 already added to the factor on the CPU, according to the images in
+  // the slides above.
+  float factor = xe_tessellation_factor_range.y;
+
+  gl_TessLevelOuter[0] = factor;
+  gl_TessLevelOuter[1] = factor;
+  gl_TessLevelOuter[2] = factor;
+  gl_TessLevelInner[0] = factor;
+}