Add support for Kubernetes ssl-redirect annotation.

[lseelenbinder]

As requested in #198.

I was not certain the acceptable way to test this, so please advise; make test does succeed.

[pleshakov]

@lseelenbinder
Thanks!

There is a small problem: Using $server.sslRedirect in the templates leads to a failure. The correct field is $server.SSLRedirect.

It is possible to test it, if you add the following lines into the Server here:

			SSL:               true,
			SSLCertificate:    "secret.pem",
			SSLCertificateKey: "secret.pem",
			SSLPorts:          []int{443},
			SSLRedirect:       true,

Without changing to $server.SSLRedirect, the test will fail.

Other than that, it works as expected!

Could you fix the problem, change the test and commit the all changes? Please squash all commits into a single one.

[lseelenbinder]

Done, @pleshakov. Let me know if there's anything else!

[pleshakov]

@lseelenbinder thx!