include/GL: add mesa_glinterop.h for OpenGL-OpenCL interop (v4.2)

include/GL: add mesa_glinterop.h for OpenGL-OpenCL interop (v4.2)

v2: - use "enum" to define stuff
v3: - more comments, define MESA_GLINTEROP_UNSUPPORTED
v4: - add mesa_glinterop_device_info::interop_version
    - more comments
    - remove #define MESA_GLINTEROP_VERSION
    - use const for "in"
v4.1: - use version numbers for structures
      - add "out_driver_data_written"
v4.2: - buf_offset & buf_size affect GL_ARRAY_BUFFER too, this is required
        for sharing suballocations within a larger buffer