Explore Schubfach/Dragonbox float to string

[vinniefalco]

See
https://www.reddit.com/r/cpp/comments/ika6ml/dragonbox_yet_another_floattostring_conversion/
https://drive.google.com/file/d/1luHhyQF9zKlM8yJ1nebU0OgVYhfC6CBN/view
https://github.com/abolz/Drachennest

[vinniefalco]

And https://github.com/jk-jeon/dragonbox

[vinniefalco]

This is something https://github.com/abolz/Drachennest

[grisumbras]

In #993 double serialization is done via Boost.Charconv (which builds on Dragonbox).