tests: extract SSL certificates from test-https.t
They can be reused in SMTPS tests.
-----BEGIN RSA PRIVATE KEY-----
MIIBOgIBAAJBAJs4LS3glAYU92bg5kPgRPNW84ewB0fWJfAKccCp1ACHAdZPeaKb
FCinVMYKAVbVqBkyrZ/Tyr8aSfMz4xO4+KsCAwEAAQJAeKDr25+Q6jkZHEbkLRP6
AfMtR+Ixhk6TJT24sbZKIC2V8KuJTDEvUhLU0CAr1nH79bDqiSsecOiVCr2HHyfT
AQIhAM2C5rHbTs9R3PkywFEqq1gU3ztCnpiWglO7/cIkuGBhAiEAwVpMSAf77kop
4h/1kWsgMALQTJNsXd4CEUK4BOxvJIsCIQCbarVAKBQvoT81jfX27AfscsxnKnh5
+MjSvkanvdFZwQIgbbcTefwt1LV4trtz2SR0i0nNcOZmo40Kl0jIquKO3qkCIH01
mJHzZr3+jQqeIFtr5P+Xqi30DJxgrnEobbJ0KFjY
-----END RSA PRIVATE KEY-----