(TK-98) Add test to ensure SSLv3 isn't supported (FOR REVIEW)

Add a test to ensure that SSLv3 isn't supported by TK Jetty9
webservers by default.

I'm throwing this up now for review. However, it depends on https://github.com/puppetlabs/clj-http-client/pull/20 getting merged and clj-http-client getting released so that the dependency can be bumped to a non-SNAPSHOT version.
There is a way to make it supported by adding it to the `:ssl-protocols` key of the webserver configuration. I can definitely add a test for that.