Hard codes endpoints in create_cas_* functions

*NOT BACKWARDS COMPATIBLE*

The previous technique was to have a configuration entry for every
CAS endpoint; `CAS_LOGIN_ROUTE`, `CAS_LOGOUT_ROUTE`, `CAS_VALIDATE_ROUTE`,
... This worked fine but with the inclusion of more CAS routes it
would be necessary to have even more configuration entries.

To simplify the configuration this commit hard codes the endpoint;
`/login`, `/logout`, `/validate`, ... and provides one configuration
entry `CAS_ROUTE_PREFIX` that allows you to modify them all.

This change is not backwards compatible therefore the version is
being bumped to `1.0.0`.