OAK-1476 - Hardcoded SecurityProvider implementation in oak-jcr Activator

-- Refactored SecurityProviderImpl to use static references to various configurations. This ensures a stable startup
-- Replaced the Activator in oak-jcr with RepositoryManager which is responsible for registering the repository. This requires explicit config to be enabled

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1576209 13f79535-47bb-0310-9956-ffa450edef68
OAK-1521 - Remove dependency on com.googlecode.json-simple from oak-core

Adding the dependency to oak-jcr such that it can be used in testcases

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1576210 13f79535-47bb-0310-9956-ffa450edef68