HTTPCLIENT-1449: split AbstractVerifier into AbstractBaseHostnameVerifier and AbstractCommonHostnameVerifier the former implementing cert extraction logic while the latter implementing CN and SubjectAlts extraction and validation logic

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1600132 13f79535-47bb-0310-9956-ffa450edef68
HTTPCLIENT-1434: add singletons for TrustSelfSignedStrategy and hostname verifiers

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1600133 13f79535-47bb-0310-9956-ffa450edef68