CSRF support

[resure]

We should determine if we want to implement CSRF support in the ExpressKit itself or recommend using some pre-made middleware like https://www.npmjs.com/package/csrf

[goshander]

When rotating the secret for signing CSRF tokens, you need to be careful and when updating the application, first add two secrets for validation, but sign only with old secret

The next time you deploy, you can already sign with a new secret and check with both old and new secrets
At third deploy you can sign with a new one and check with new secret

function checkToken(
        userId: string,
        timestamp: string | number = getUnixTime(),
        tokenValue: string,
    ) {
        for (let i = 0; i < csrfSecrets.length; i += 1) {
            if (buildToken(userId, timestamp, csrfSecrets[i]) === tokenValue) {
                return true;
            }
        }
        return false;
    }

    function buildToken(
        userId: string,
        timestamp: string | number = getUnixTime(),
        csrfSecret: string = csrfSecrets[0],
    ) {
        try {
...