Add CMake installation rules

[ahesham-arm]

Add installation rules for all the binary targets.

Targets are installed under <CMAKE_INSTALL_PREFIX>/bin/<CONFIG> where <CONFIG> is CMAKE_BUILD_TYPE for single-config generators, e.g. Unix Makefiles and Ninja, or the build configuration for multi-config generators, e.g. Ninja Multi-Config and Visual Studio.

This creates the target install on Unix and INSTALL on Windows.

[bashbaug]

Can you please also check if we need to install the Vulkan SPIR-V files? See: #2055

At some point it would be nice to install the OpenCL SPIR-V files in a sensible place also (and ideally, to auto-build them if any of the source spvasm changes), but this is less critical because the path to the OpenCL SPIR-V files can be set using --spirv-binaries-path.

[ahesham-arm]

Can you please also check if we need to install the Vulkan SPIR-V files? See: #2055

You're right, yes they do. I note that the CMakeLists.txt for the Vulkan shaders is wrong in two ways:

1. Project configuration and building are two distinct steps. execute_process runs in configuration time and should not be used for generating files. Instead, add_custom_command and add_custom_target should be used to define build targets that get executed at build times.
2. The source directory should never be modified by the configuration or build processes, thanks for fixing that in compile Vulkan SPIR-V shaders in CMAKE_CURRENT_BINARY_DIR #2055.

[ahesham-arm]

Fixed the way the Vulkan shaders are generated in #2199 as a requirement for having correct installation rules for them.