Added ability to define a different SSL port for the redirects

This patch allows to specify another HTTPS/SSL port than 443 (for example, 8443 during development) by adding a options-map with the key `:ssl-port` to the `wrap-ssl-redirect` function.

`request-url` is an adapted version of the one in `ring.util.request`, which also takes the port into account.

Please feel free to refactor the code to your liking.