Support CSP nonce

[sdemjanenko]

I am running in to an issue with the inline styles that this library is injecting:

react-spinners/src/helpers/animation.ts

Line 9 in 6f6d0f8

document.head.appendChild(styleEl);

. This could be fixed by exposing a Provider which can then receive a nonce to use for the inline style injection. See emotion's solution for this: https://emotion.sh/docs/@emotion/cache#nonce.

Im not sure if animations are the only place in the codebase that inject inline styles. All places would need to be updated to use a provided nonce.