Move shaders into glsl and hlsl directories

Move `data/shaders` to `data/shaders/glsl`
Move `data/hlsl` to `data/shaders/hlsl`

Fix up shader paths in the cpp files to point to the new glsl location.

`data/shaders/hlsl/compile.py` still overwrites the glsl .spv files (for
now).

Issue: #723

data/hlsl/README.md

@@ -1,18 +0,0 @@
-## HLSL Shaders
-
-This directory contains a fork of the shaders found in [data/shaders](https://github.com/SaschaWillems/Vulkan/tree/master/data/shaders), re-written in HLSL.
-These can be compiled with [DXC](https://github.com/microsoft/DirectXShaderCompiler) using the `compile.py` script.
-
-### Known issues
-
-- specialization constants can't be used to specify array size.
-- `gl_PointCoord` not supported. HLSL has no equivalent. We changed the shaders to calulate the PointCoord manually in the shader. (`computenbody`, `computeparticles`, `particlefire` examples).
-- HLSL doesn't have inverse operation (`deferred`, `hdr`, `instancing`, `skeletalanimation` & `texturecubemap` examples).
-- `modf` causes compilation to fail without errors or warnings. (`modf` not used by any examples, easily confused with fmod)
-- In `specializationconstants` example, shader compilation fails with error:
-    ```
-    --- Error msg: fatal error: failed to optimize SPIR-V: Id 10 is defined more than once
-    ```
-  When multiple constant ids are defined and have different types. We work around this problem by making all constant ids the same type, then use `asfloat`, `asint` or `asuint` to get the original value in the shader.
-- `gl_RayTmaxNV` not supported. (`nv_ray_tracing_*` examples)
-- HLSL interface for sparse residency textures is different from GLSL interface. After translating from HLSL to GLSL the shaders behave slightly different. Most important parts do behave identically though.