Get rid of BOOST_COMPUTE_ADAPT_STRUCT integrating boost::pfr

[denzor200]

https://github.com/boostorg/pfr

Boost PFR - it's a small library that provides basic reflection for user defined types without any boilerplated macro. Now the library have everything required from Boost Compute library (including reflection of field names) and might be integrated in order to get rid of BOOST_COMPUTE_ADAPT_STRUCT macro.

Don't hesitate to ask any question regarding PFR, my pleasure to provide as much help with development as it required.

[denzor200]

And if here is no active contributor who is free to make the PR - just let me know at least somebody can be reviewer and then I will create PR by myself