Previously we had the logic for setting up the ports on the server in
server_main. This makes for messy testing of this functionality. As
such, this setup logic has been moved to a public function which can be
tested easily.

This commit does not change any exists test, but modifies the testutil
for creating a cache server.

Previously, we had been only testing an unsecured CAS server. As such,
no authentication mechanisms were tested. This commit adapts existing
tests to ensure that a secured CAS server is also tested alongside
unsecured configurations.

This commit introduces two data files which are used in part of the
testing process: a server private key, and a server certificate. The
server private key is of size 4096 bytes. The server certificate is for
the name "localhost" and has an expiration set to 1000 years in the
future, so there should be little concern of the expiration of this
testing artifact.