Support keyframes and createGlobalStyle in "@linaria/react"

[otomad]

Describe the feature

These two functions come from Styled Components.

keyframes function will create a CSS keyframes with a unique name, to make sure that there are no naming conflicts.

You can even inline the declaration without having to think of a keyframes name:

div {
    animation: ${keyframes`
        from {
            opacity: 0;
        }
    `} ease-out 1s;
}

createGlobalStyle will create a global style for every components to use, without to write it in a single CSS file.

Motivation

This will make it easier to switch Styled Components to Linaria.

[KutnerUri]

I agree, right now keyframes are preprocessed and it feels like dark magic.
it would be nice to have a dedicated function for that