Make Critical CSS

[yuriipavlov]

It is necessary to create a critical CSS. It should be loaded in a header, be small.

Need to provide inline embedding critical CSS. This should include: reset styles, grid styles, common colors, header, header menu. Everything else needs to be connected to the footer. Including font styles. Fonts should be loaded asynchronously. To do this, it's need to make separate connection functions for different hooks. For example wp_enqueue_scripts and wp_footer

This Issue is important for PageSpeed

[yuriipavlov]

merged to develop