hard-coded domains config file in SSOCookieManager

[pdowler]

The hard-coded filename (ac-domains.properties) should be replaced with an alternate mechanism that allows the login service that generates cookies to pass in the domain list instead of having this particular file. In OpenCADC this effects the login code in cadc-access-control-server as that is where tokens are generated. The filename and use of file should get moved to over there.