Add preload support to Strict-Transport-Security

[OArtyomov]

Strict-Transport-Security configuration
Problem:
Response header "Strict-Transport-Security" should contain value "max-age=31536000;includeSubdomains; preload". There is no possibility to do it in class HstsConfig now. Only "max-age=31536000; includeSubdomains" supportable.

[rwinch]

Thanks for the ticket. Would you be willing to submit a PR for this? If you need help, I'd be glad to guide you through the process

[ankurpathak]

I would like to take this one.

[rwinch]

@ankurpathak Thank you the issue is yours.

[ankurpathak]

Pull request for the issue:
#6321