* Support LDAP authentication/authorization
* fixed integration-tests
* fixed Travis CI build errors related to druid-security module
* fixed failing test
* fixed failing test header
* added comments, force build
* fixes for strict compilation spotbugs checks
* removed authenticator rolling credential update feature
* removed escalator rolling credential update feature
* fixed teamcity inspection deprecated API usage error
* fixed checkstyle execution error, removed unused import
* removed cached config as part of removing authenticator rolling credential update feature
* removed config bundle entity as part of removing authenticator rolling credential update feature
* refactored ldao configuration
* added support for SSLContext configuration and TLSCertificateChecker
* removed check to return authentication failure when user has no group assigned, will be checked and handled by the authorizer
* Separate out authorizer checks between metadata-backed store user and LDAP user/groups
* refactored BasicSecuritySSLSocketFactory usage to fix strict compilation spotbugs checks
* fixes build issue
* final review comments updates
* final review comments updates
* fixed LGTM and spellcheck alerts
* Fixed Avatica auth failure error message check
* Updated metadata credentials validator exception message string, replaced DB with metadata store
* move google ext docs from contrib to core
* fix links
* revert unintended change
* more links, add note to example ext doc that it was removed, unlink from sidebar