feat: Support CSRF token retrieval from header "X-CSRF-Token"

[masterT]

Retrieve the request CSRF token from the HTTP header X-CSRF-Token in the case the params _csrf_token is not provided.

Reference:

• #420

[timriley]

Thanks for putting this together, @masterT! However, rather than leave this as a hook inside actions for users to override, I'd prefer we just fully build in support for checking the header for the CSRF token in addition to the request's params.

Would you like to have a go at doing that?

[masterT]

Sure, I will craft something.

[masterT]

I did implement your suggestion, this is ready for review. 🙂 @timriley